diff --git a/app/Actions/Post/UpdatePost.php b/app/Actions/Post/UpdatePost.php
index 3b0dd632e..5236c7c24 100644
--- a/app/Actions/Post/UpdatePost.php
+++ b/app/Actions/Post/UpdatePost.php
@@ -49,20 +49,20 @@ public static function execute(Workspace $workspace, Post $post, array $data): a
 
                 foreach (data_get($data, 'platforms', []) as $platformData) {
                     $updateData = ['enabled' => true];
+                    $needsExistingRow = data_get($platformData, 'meta') !== null || Arr::has($platformData, 'media_ids');
+                    $postPlatform = $needsExistingRow
+                        ? $post->postPlatforms()->where('id', data_get($platformData, 'id'))->first()
+                        : null;
 
                     if (data_get($platformData, 'content_type') !== null) {
                         $updateData['content_type'] = data_get($platformData, 'content_type');
                     }
 
-                    if (data_get($platformData, 'meta') !== null) {
-                        $postPlatform = $post->postPlatforms()->where('id', data_get($platformData, 'id'))->first();
-
-                        if ($postPlatform) {
-                            $updateData['meta'] = array_filter(
-                                array_merge($postPlatform->meta ?? [], data_get($platformData, 'meta') ?? []),
-                                fn (mixed $value): bool => $value !== null,
-                            );
-                        }
+                    if (data_get($platformData, 'meta') !== null && $postPlatform) {
+                        $updateData['meta'] = array_filter(
+                            array_merge($postPlatform->meta ?? [], data_get($platformData, 'meta') ?? []),
+                            fn (mixed $value): bool => $value !== null,
+                        );
                     }
 
                     $post->postPlatforms()
@@ -74,11 +74,11 @@ public static function execute(Workspace $workspace, Post $post, array $data): a
                     // client that never sends it must not accidentally clear every
                     // platform's scoping), while an explicit empty array clears it
                     // back to "publish every media item on the post" (see
-                    // PostPlatform::scopedMediaItems()).
-                    if (Arr::has($platformData, 'media_ids')) {
-                        $postPlatform = $post->postPlatforms()->where('id', data_get($platformData, 'id'))->first();
-
-                        $postPlatform?->media()->sync(data_get($platformData, 'media_ids', []));
+                    // PostPlatform::scopedMediaItems()). $postPlatform is already
+                    // resolved above via $needsExistingRow when media_ids is present,
+                    // no need to re-fetch it here.
+                    if (Arr::has($platformData, 'media_ids') && $postPlatform) {
+                        $postPlatform->media()->sync(data_get($platformData, 'media_ids', []));
                     }
                 }
             }
diff --git a/app/Http/Controllers/App/PostController.php b/app/Http/Controllers/App/PostController.php
index 9b0702eb8..a8f816d1a 100644
--- a/app/Http/Controllers/App/PostController.php
+++ b/app/Http/Controllers/App/PostController.php
@@ -248,7 +248,13 @@ public function edit(Request $request, Post $post): Response|RedirectResponse
             SyncPostPlatforms::execute($post);
         }
 
-        $post->load(['postPlatforms.socialAccount', 'labels']);
+        $post->load(['postPlatforms.socialAccount', 'postPlatforms.media', 'labels']);
+
+        // `media_ids` is only appended here, not globally on the model, so the
+        // Index/Calendar listings (which don't eager-load `media`) don't take
+        // an unwanted lazy-load hit on every post_platform they render.
+        $post->postPlatforms->each(fn (PostPlatform $postPlatform) => $postPlatform->append('media_ids'));
+
         $socialAccounts = $workspace->socialAccounts()->active()->get();
         $labels = $workspace->labels;
         $signatures = $workspace->signatures;
diff --git a/app/Http/Requests/App/Post/UpdatePostRequest.php b/app/Http/Requests/App/Post/UpdatePostRequest.php
index 81e1e6666..da83b2f3d 100644
--- a/app/Http/Requests/App/Post/UpdatePostRequest.php
+++ b/app/Http/Requests/App/Post/UpdatePostRequest.php
@@ -55,6 +55,11 @@ public function rules(): array
                 'string',
                 Rule::in(array_column(ContentType::cases(), 'value')),
             ],
+            // Per-platform media assignment (Edit.vue's media toggle grid). An
+            // id must be one of the media items this same request is saving on
+            // the post, never an arbitrary/unrelated media id (IDOR guard).
+            'platforms.*.media_ids' => ['sometimes', 'array'],
+            'platforms.*.media_ids.*' => ['string', Rule::in($this->postMediaIds())],
             ...PostPlatformMetaRules::rules(),
             'label_ids' => ['sometimes', 'array'],
             'label_ids.*' => ['uuid', Rule::exists('workspace_labels', 'id')->where('workspace_id', $this->user()->currentWorkspace->id)],
@@ -150,6 +155,17 @@ private function addMediaCompatibilityErrors(Validator $validator): void
         }
     }
 
+    /**
+     * The media ids this request is saving on the post itself, the only ids
+     * a `platforms.*.media_ids` entry is allowed to reference.
+     *
+     * @return array<int, string>
+     */
+    private function postMediaIds(): array
+    {
+        return collect($this->input('media', []))->pluck('id')->filter()->all();
+    }
+
     /**
      * @return Collection<int|string, Platform>
      */
diff --git a/app/Models/PostPlatform.php b/app/Models/PostPlatform.php
index 28b4e977c..b8110d211 100644
--- a/app/Models/PostPlatform.php
+++ b/app/Models/PostPlatform.php
@@ -104,15 +104,30 @@ public function scopedMediaItems(): Collection
     }
 
     /**
-     * Only platforms still enabled for publishing — disabled ones are
+     * Only platforms still enabled for publishing (disabled ones are
      * excluded from PublishPost, so anything else that mirrors publish
-     * eligibility (previews, validation, proactive checks) must too.
+     * eligibility (previews, validation, proactive checks) must too).
      */
     public function scopeEnabled(Builder $query): Builder
     {
         return $query->where('post_platforms.enabled', true);
     }
 
+    /**
+     * The ids of media items currently scoped to this platform. Empty means
+     * "no scoping, applies to every post media item", see scopedMediaItems().
+     * Only used for the editor's per-platform media assignment UI, so this
+     * relies on `media` already being eager-loaded (or explicitly appended
+     * via `append('media_ids')`, see PostController::edit()) to avoid a lazy
+     * load nobody asked for on every other page that serializes this model.
+     *
+     * @return array<int, string>
+     */
+    public function getMediaIdsAttribute(): array
+    {
+        return $this->media->pluck('id')->all();
+    }
+
     /**
      * Get display name, falling back to snapshot if account was deleted.
      */
diff --git a/lang/ar/posts.php b/lang/ar/posts.php
index 43445d185..b57bd1588 100644
--- a/lang/ar/posts.php
+++ b/lang/ar/posts.php
@@ -344,6 +344,11 @@
         'drop_zone_subtitle' => 'اسحب الملفات وأفلتها أو انقر للتصفح',
         'add' => 'إضافة',
         'publish_to' => 'النشر إلى',
+        'media_assignment' => [
+            'label' => 'الوسائط لهذه القناة',
+            'included' => 'مضمّن لهذه القناة',
+            'excluded' => 'مستبعد من هذه القناة',
+        ],
         'organize' => 'تنظيم',
         'signatures' => 'التوقيعات',
         'view_on_platform' => 'العرض على المنصة',
diff --git a/lang/de/posts.php b/lang/de/posts.php
index 481bc0c33..5bfde2ed6 100644
--- a/lang/de/posts.php
+++ b/lang/de/posts.php
@@ -346,6 +346,11 @@
         'drop_zone_subtitle' => 'Dateien ziehen & ablegen oder zum Durchsuchen klicken',
         'add' => 'Hinzufügen',
         'publish_to' => 'Veröffentlichen auf',
+        'media_assignment' => [
+            'label' => 'Medien für diesen Kanal',
+            'included' => 'Enthalten für diesen Kanal',
+            'excluded' => 'Ausgeschlossen von diesem Kanal',
+        ],
         'organize' => 'Organisieren',
         'signatures' => 'Signaturen',
         'view_on_platform' => 'Auf der Plattform ansehen',
diff --git a/lang/el/posts.php b/lang/el/posts.php
index dbf866950..dd4c7b1ff 100644
--- a/lang/el/posts.php
+++ b/lang/el/posts.php
@@ -344,6 +344,11 @@
         'drop_zone_subtitle' => 'Σύρετε και αποθέστε αρχεία ή κάντε κλικ για αναζήτηση',
         'add' => 'Προσθήκη',
         'publish_to' => 'Δημοσίευση σε',
+        'media_assignment' => [
+            'label' => 'Πολυμέσα για αυτό το κανάλι',
+            'included' => 'Περιλαμβάνεται σε αυτό το κανάλι',
+            'excluded' => 'Εξαιρείται από αυτό το κανάλι',
+        ],
         'organize' => 'Οργάνωση',
         'signatures' => 'Υπογραφές',
         'view_on_platform' => 'Προβολή στην πλατφόρμα',
diff --git a/lang/en/posts.php b/lang/en/posts.php
index 4add724af..00f622e33 100644
--- a/lang/en/posts.php
+++ b/lang/en/posts.php
@@ -344,6 +344,11 @@
         'drop_zone_subtitle' => 'Drag & drop files or click to browse',
         'add' => 'Add',
         'publish_to' => 'Publish to',
+        'media_assignment' => [
+            'label' => 'Media for this channel',
+            'included' => 'Included for this channel',
+            'excluded' => 'Excluded from this channel',
+        ],
         'organize' => 'Organize',
         'signatures' => 'Signatures',
         'view_on_platform' => 'View on platform',
diff --git a/lang/es/posts.php b/lang/es/posts.php
index 7eb08c207..0c22d09ea 100644
--- a/lang/es/posts.php
+++ b/lang/es/posts.php
@@ -338,6 +338,11 @@
         'drop_zone_subtitle' => 'Arrastra archivos o haz clic para seleccionar',
         'add' => 'Añadir',
         'publish_to' => 'Publicar en',
+        'media_assignment' => [
+            'label' => 'Contenido para este canal',
+            'included' => 'Incluido en este canal',
+            'excluded' => 'Excluido de este canal',
+        ],
         'organize' => 'Organizar',
         'no_labels' => 'Todavía no hay etiquetas creadas',
         'pick_time' => 'Elegir hora',
diff --git a/lang/fr/posts.php b/lang/fr/posts.php
index 183ae393e..a6a640c9c 100644
--- a/lang/fr/posts.php
+++ b/lang/fr/posts.php
@@ -344,6 +344,11 @@
         'drop_zone_subtitle' => 'Glissez-déposez des fichiers ou cliquez pour parcourir',
         'add' => 'Ajouter',
         'publish_to' => 'Publier sur',
+        'media_assignment' => [
+            'label' => 'Contenu pour ce canal',
+            'included' => 'Inclus pour ce canal',
+            'excluded' => 'Exclu de ce canal',
+        ],
         'organize' => 'Organiser',
         'signatures' => 'Signatures',
         'view_on_platform' => 'Voir sur la plateforme',
diff --git a/lang/it/posts.php b/lang/it/posts.php
index f6b3198e9..e093dbc52 100644
--- a/lang/it/posts.php
+++ b/lang/it/posts.php
@@ -344,6 +344,11 @@
         'drop_zone_subtitle' => 'Trascina e rilascia i file oppure clicca per sfogliare',
         'add' => 'Aggiungi',
         'publish_to' => 'Pubblica su',
+        'media_assignment' => [
+            'label' => 'Contenuti per questo canale',
+            'included' => 'Incluso per questo canale',
+            'excluded' => 'Escluso da questo canale',
+        ],
         'organize' => 'Organizza',
         'signatures' => 'Firme',
         'view_on_platform' => 'Visualizza sulla piattaforma',
diff --git a/lang/ja/posts.php b/lang/ja/posts.php
index 731c23ebf..aad9de7bf 100644
--- a/lang/ja/posts.php
+++ b/lang/ja/posts.php
@@ -344,6 +344,11 @@
         'drop_zone_subtitle' => 'ファイルをドラッグ＆ドロップするか、クリックして参照',
         'add' => '追加',
         'publish_to' => '公開先',
+        'media_assignment' => [
+            'label' => 'このチャンネルのメディア',
+            'included' => 'このチャンネルに含まれています',
+            'excluded' => 'このチャンネルから除外されています',
+        ],
         'organize' => '整理',
         'signatures' => '署名',
         'view_on_platform' => 'プラットフォームで表示',
diff --git a/lang/ko/posts.php b/lang/ko/posts.php
index f93cd8564..934c59e54 100644
--- a/lang/ko/posts.php
+++ b/lang/ko/posts.php
@@ -344,6 +344,11 @@
         'drop_zone_subtitle' => '파일을 끌어다 놓거나 클릭하여 찾아보기',
         'add' => '추가',
         'publish_to' => '게시 대상',
+        'media_assignment' => [
+            'label' => '이 채널의 미디어',
+            'included' => '이 채널에 포함됨',
+            'excluded' => '이 채널에서 제외됨',
+        ],
         'organize' => '정리',
         'signatures' => '서명',
         'view_on_platform' => '플랫폼에서 보기',
diff --git a/lang/nl/posts.php b/lang/nl/posts.php
index 63c37c615..4a97b382c 100644
--- a/lang/nl/posts.php
+++ b/lang/nl/posts.php
@@ -344,6 +344,11 @@
         'drop_zone_subtitle' => 'Sleep bestanden hierheen of klik om te bladeren',
         'add' => 'Toevoegen',
         'publish_to' => 'Publiceren naar',
+        'media_assignment' => [
+            'label' => 'Media voor dit kanaal',
+            'included' => 'Inbegrepen voor dit kanaal',
+            'excluded' => 'Uitgesloten van dit kanaal',
+        ],
         'organize' => 'Organiseren',
         'signatures' => 'Handtekeningen',
         'view_on_platform' => 'Bekijken op platform',
diff --git a/lang/pl/posts.php b/lang/pl/posts.php
index e397a7474..45f5c37d9 100644
--- a/lang/pl/posts.php
+++ b/lang/pl/posts.php
@@ -344,6 +344,11 @@
         'drop_zone_subtitle' => 'Przeciągnij i upuść pliki lub kliknij, aby przeglądać',
         'add' => 'Dodaj',
         'publish_to' => 'Publikuj na',
+        'media_assignment' => [
+            'label' => 'Media dla tego kanału',
+            'included' => 'Uwzględnione dla tego kanału',
+            'excluded' => 'Wykluczone z tego kanału',
+        ],
         'organize' => 'Organizuj',
         'signatures' => 'Sygnatury',
         'view_on_platform' => 'Zobacz na platformie',
diff --git a/lang/pt-BR/posts.php b/lang/pt-BR/posts.php
index 37018fac1..e522bc35e 100644
--- a/lang/pt-BR/posts.php
+++ b/lang/pt-BR/posts.php
@@ -338,6 +338,11 @@
         'drop_zone_subtitle' => 'Arraste arquivos ou clique para selecionar',
         'add' => 'Adicionar',
         'publish_to' => 'Publicar em',
+        'media_assignment' => [
+            'label' => 'Mídia para este canal',
+            'included' => 'Incluído neste canal',
+            'excluded' => 'Excluído deste canal',
+        ],
         'organize' => 'Organizar',
         'no_labels' => 'Nenhuma etiqueta criada ainda',
         'pick_time' => 'Escolher horário',
diff --git a/lang/ru/posts.php b/lang/ru/posts.php
index 947601df7..34f664974 100644
--- a/lang/ru/posts.php
+++ b/lang/ru/posts.php
@@ -344,6 +344,11 @@
         'drop_zone_subtitle' => 'Перетащите файлы или нажмите для выбора',
         'add' => 'Добавить',
         'publish_to' => 'Опубликовать в',
+        'media_assignment' => [
+            'label' => 'Медиа для этого канала',
+            'included' => 'Включено для этого канала',
+            'excluded' => 'Исключено из этого канала',
+        ],
         'organize' => 'Организовать',
         'signatures' => 'Подписи',
         'view_on_platform' => 'Открыть на платформе',
diff --git a/lang/tr/posts.php b/lang/tr/posts.php
index 5faa9a22f..612b8c160 100644
--- a/lang/tr/posts.php
+++ b/lang/tr/posts.php
@@ -346,6 +346,11 @@
         'drop_zone_subtitle' => 'Dosyaları sürükleyip bırakın veya göz atmak için tıklayın',
         'add' => 'Ekle',
         'publish_to' => 'Şuraya yayınla',
+        'media_assignment' => [
+            'label' => 'Bu kanal için medya',
+            'included' => 'Bu kanala dahil',
+            'excluded' => 'Bu kanaldan hariç',
+        ],
         'organize' => 'Düzenle',
         'signatures' => 'İmzalar',
         'view_on_platform' => 'Platformda görüntüle',
diff --git a/lang/uk/posts.php b/lang/uk/posts.php
index 4ee02d9fe..9df90af7c 100644
--- a/lang/uk/posts.php
+++ b/lang/uk/posts.php
@@ -344,6 +344,11 @@
         'drop_zone_subtitle' => 'Перетягніть файли або натисніть, щоб обрати',
         'add' => 'Додати',
         'publish_to' => 'Опублікувати в',
+        'media_assignment' => [
+            'label' => 'Медіа для цього каналу',
+            'included' => 'Включено для цього каналу',
+            'excluded' => 'Виключено з цього каналу',
+        ],
         'organize' => 'Організувати',
         'signatures' => 'Підписи',
         'view_on_platform' => 'Переглянути на платформі',
diff --git a/lang/zh/posts.php b/lang/zh/posts.php
index c8e519378..47ed5487d 100644
--- a/lang/zh/posts.php
+++ b/lang/zh/posts.php
@@ -344,6 +344,11 @@
         'drop_zone_subtitle' => '拖放文件或点击浏览',
         'add' => '添加',
         'publish_to' => '发布到',
+        'media_assignment' => [
+            'label' => '此频道的媒体',
+            'included' => '已包含在此频道',
+            'excluded' => '已从此频道排除',
+        ],
         'organize' => '整理',
         'signatures' => '签名',
         'view_on_platform' => '在平台上查看',
diff --git a/resources/js/components/ChannelConfigurator.vue b/resources/js/components/ChannelConfigurator.vue
index 813d5dff0..99834f69e 100644
--- a/resources/js/components/ChannelConfigurator.vue
+++ b/resources/js/components/ChannelConfigurator.vue
@@ -6,6 +6,7 @@ import DiscordSettings from '@/components/posts/editor/DiscordSettings.vue';
 import FacebookSettings from '@/components/posts/editor/FacebookSettings.vue';
 import InstagramSettings from '@/components/posts/editor/InstagramSettings.vue';
 import LinkedInSettings from '@/components/posts/editor/LinkedInSettings.vue';
+import MediaAssignmentGrid from '@/components/posts/editor/MediaAssignmentGrid.vue';
 import PinterestSettings from '@/components/posts/editor/PinterestSettings.vue';
 import TikTokSettings from '@/components/posts/editor/TikTokSettings.vue';
 import { Avatar } from '@/components/ui/avatar';
@@ -33,6 +34,7 @@ const emit = defineEmits<{
     toggle: [id: string];
     'update:contentType': [id: string, value: string];
     'update:meta': [id: string, value: Record<string, any>];
+    'update:mediaIds': [id: string, mediaIds: string[]];
 }>();
 
 const isSelected = (id: string): boolean => props.selectedIds.includes(id);
@@ -121,6 +123,13 @@ const settingsProps = (channel: Channel) => ({
         <slot />
 
         <template v-for="channel in selectedChannels" :key="channel.id">
+            <MediaAssignmentGrid
+                :platform="channel.platform"
+                :media="media"
+                :selected-media-ids="channel.mediaIds"
+                :disabled="disabled"
+                @update:selected-media-ids="(ids) => emit('update:mediaIds', channel.id, ids)"
+            />
             <InstagramSettings
                 v-if="channel.platform === Platform.Instagram || channel.platform === Platform.InstagramFacebook"
                 v-bind="settingsProps(channel)"
diff --git a/resources/js/components/posts/editor/MediaAssignmentGrid.vue b/resources/js/components/posts/editor/MediaAssignmentGrid.vue
new file mode 100644
index 000000000..a054f43c5
--- /dev/null
+++ b/resources/js/components/posts/editor/MediaAssignmentGrid.vue
@@ -0,0 +1,95 @@
+<script setup lang="ts">
+import { IconCheck } from '@tabler/icons-vue';
+
+import { Badge } from '@/components/ui/badge';
+import { Tooltip, TooltipContent, TooltipProvider, TooltipTrigger } from '@/components/ui/tooltip';
+import { getPlatformLogo } from '@/composables/usePlatformLogo';
+import { isVideo } from '@/lib/mediaType';
+import type { MediaItem } from '@/types/media';
+
+const props = withDefaults(
+    defineProps<{
+        platform: string;
+        media: MediaItem[];
+        selectedMediaIds: string[];
+        disabled?: boolean;
+    }>(),
+    { disabled: false },
+);
+
+const emit = defineEmits<{
+    'update:selectedMediaIds': [ids: string[]];
+}>();
+
+// An empty array means "no scoping yet", the current, unscoped behaviour
+// (every item applies to every platform), so every toggle renders as on
+// until the user narrows the selection for the first time.
+const isIncluded = (mediaId: string): boolean =>
+    props.selectedMediaIds.length === 0 || props.selectedMediaIds.includes(mediaId);
+
+const toggle = (mediaId: string): void => {
+    const current = props.selectedMediaIds.length === 0
+        ? props.media.map((item) => item.id)
+        : props.selectedMediaIds;
+
+    if (isIncluded(mediaId)) {
+        // An empty array means "unscoped, applies to all" everywhere this is
+        // read (scopedMediaItems(), the grid itself), so it can never also
+        // mean "explicitly none". Deselecting the last remaining item would
+        // silently flip back to "all", the opposite of what was just done,
+        // so the last one stays on: a platform always publishes something.
+        if (current.length <= 1) return;
+
+        emit('update:selectedMediaIds', current.filter((id) => id !== mediaId));
+        return;
+    }
+
+    emit('update:selectedMediaIds', [...current, mediaId]);
+};
+</script>
+
+<template>
+    <div v-if="media.length > 1" class="rounded-xl border-2 border-foreground bg-card p-4 shadow-2xs">
+        <div class="mb-3 flex items-center gap-2">
+            <span class="inline-flex size-6 shrink-0 items-center justify-center overflow-hidden rounded-full border-2 border-foreground bg-card shadow-2xs">
+                <img :src="getPlatformLogo(platform)" :alt="platform" class="size-full object-cover" />
+            </span>
+            <p class="text-[11px] font-black uppercase tracking-widest text-foreground/60">
+                {{ $t('posts.edit.media_assignment.label') }}
+            </p>
+        </div>
+        <div class="flex flex-wrap gap-2">
+            <TooltipProvider v-for="item in media" :key="item.id" :delay-duration="200">
+                <Tooltip>
+                    <TooltipTrigger as-child>
+                        <button
+                            type="button"
+                            class="relative flex size-14 shrink-0 items-center justify-center overflow-hidden rounded-lg border-2 transition-opacity disabled:cursor-not-allowed"
+                            :class="isIncluded(item.id) ? 'border-foreground opacity-100' : 'border-foreground/30 opacity-40'"
+                            :disabled="disabled"
+                            :aria-pressed="isIncluded(item.id)"
+                            :data-testid="`media-assignment-${item.id}`"
+                            @click="toggle(item.id)"
+                        >
+                            <video v-if="isVideo(item)" :src="item.url" class="size-full object-cover" muted playsinline />
+                            <img v-else :src="item.url" :alt="item.meta?.alt_text ?? item.original_filename ?? ''" class="size-full object-cover" />
+                            <Badge
+                                v-if="isIncluded(item.id)"
+                                variant="success"
+                                class="absolute -bottom-1 -right-1 size-5 rounded-full p-0"
+                                :data-testid="`media-assignment-${item.id}-on`"
+                            >
+                                <IconCheck class="size-3" stroke-width="3" />
+                            </Badge>
+                        </button>
+                    </TooltipTrigger>
+                    <TooltipContent>
+                        <p class="text-xs">
+                            {{ isIncluded(item.id) ? $t('posts.edit.media_assignment.included') : $t('posts.edit.media_assignment.excluded') }}
+                        </p>
+                    </TooltipContent>
+                </Tooltip>
+            </TooltipProvider>
+        </div>
+    </div>
+</template>
diff --git a/resources/js/components/posts/editor/PostEditorTabs.vue b/resources/js/components/posts/editor/PostEditorTabs.vue
index 471245178..482c305ee 100644
--- a/resources/js/components/posts/editor/PostEditorTabs.vue
+++ b/resources/js/components/posts/editor/PostEditorTabs.vue
@@ -60,6 +60,7 @@ const props = defineProps<{
     selectedPlatformIds: string[];
     platformMeta: Record<string, Record<string, any>>;
     platformContentTypes: Record<string, string>;
+    platformMediaIds: Record<string, string[]>;
     platformIssues: Record<string, PlatformIssue>;
     platformConfigs: Record<string, any>;
     labels: { id: string; name: string; color: string }[];
@@ -79,6 +80,7 @@ const emit = defineEmits<{
     (e: 'toggle-label', labelId: string): void;
     (e: 'update:platformMeta', platformId: string, meta: Record<string, any>): void;
     (e: 'update:platformContentType', platformId: string, contentType: string): void;
+    (e: 'update:platformMediaIds', platformId: string, mediaIds: string[]): void;
 }>();
 
 const commentsTabRef = ref<InstanceType<typeof CommentsTab> | null>(null);
@@ -122,6 +124,7 @@ defineExpose({
                 :platform-configs="platformConfigs"
                 :platform-meta="platformMeta"
                 :platform-content-types="platformContentTypes"
+                :platform-media-ids="platformMediaIds"
                 :platform-issues="platformIssues"
                 :tiktok-creator-infos="tiktokCreatorInfos"
                 :pinterest-boards="pinterestBoards"
@@ -130,6 +133,7 @@ defineExpose({
                 @toggle-label="(id) => emit('toggle-label', id)"
                 @update:platform-meta="(id, meta) => emit('update:platformMeta', id, meta)"
                 @update:platform-content-type="(id, contentType) => emit('update:platformContentType', id, contentType)"
+                @update:platform-media-ids="(id, mediaIds) => emit('update:platformMediaIds', id, mediaIds)"
             />
         </TabsContent>
 
diff --git a/resources/js/components/posts/editor/ScheduleTab.vue b/resources/js/components/posts/editor/ScheduleTab.vue
index 8ebf737e6..f2e535c0b 100644
--- a/resources/js/components/posts/editor/ScheduleTab.vue
+++ b/resources/js/components/posts/editor/ScheduleTab.vue
@@ -77,6 +77,7 @@ const props = defineProps<{
     platformConfigs: Record<string, PlatformConfig>;
     platformMeta: Record<string, Record<string, any>>;
     platformContentTypes: Record<string, string>;
+    platformMediaIds: Record<string, string[]>;
     platformIssues?: Record<string, PlatformIssue>;
     tiktokCreatorInfos?: Record<string, TikTokCreatorInfo> | null;
     pinterestBoards?: Record<string, PinterestBoardsPayload> | null;
@@ -88,6 +89,7 @@ const emit = defineEmits<{
     toggleLabel: [labelId: string];
     'update:platformMeta': [platformId: string, meta: Record<string, any>];
     'update:platformContentType': [platformId: string, contentType: string];
+    'update:platformMediaIds': [platformId: string, mediaIds: string[]];
 }>();
 
 const getPublishConfig = (pp: PostPlatform): Record<string, any> | null =>
@@ -145,6 +147,7 @@ const channels = computed<Channel[]>(() =>
         socialAccount: pp.social_account,
         contentType: props.platformContentTypes[pp.id] ?? pp.content_type ?? '',
         meta: props.platformMeta[pp.id] ?? {},
+        mediaIds: props.platformMediaIds[pp.id] ?? [],
         issue: props.platformIssues?.[pp.id]?.message ?? null,
         issueDocsUrl: props.platformIssues?.[pp.id]?.docsUrl ?? null,
         status: pp.status,
@@ -172,6 +175,7 @@ const channels = computed<Channel[]>(() =>
                 @toggle="(id: string) => emit('togglePlatform', id)"
                 @update:content-type="(id: string, value: string) => emit('update:platformContentType', id, value)"
                 @update:meta="(id: string, value: Record<string, any>) => emit('update:platformMeta', id, value)"
+                @update:media-ids="(id: string, ids: string[]) => emit('update:platformMediaIds', id, ids)"
             >
                 <div v-if="postPlatforms.some(pp => pp.status !== PostPlatformStatus.Pending)">
                     <p class="mb-2 text-[11px] font-black uppercase tracking-widest text-foreground/60">
diff --git a/resources/js/pages/posts/Edit.vue b/resources/js/pages/posts/Edit.vue
index c9b0218bc..cebf42b76 100644
--- a/resources/js/pages/posts/Edit.vue
+++ b/resources/js/pages/posts/Edit.vue
@@ -53,6 +53,7 @@ interface PostPlatform {
     published_at: string | null;
     social_account: SocialAccount | null;
     meta?: Record<string, any>;
+    media_ids?: string[];
 }
 
 interface Post {
@@ -135,6 +136,15 @@ const updatePlatformContentType = (platformId: string, contentType: string) => {
     platformContentTypes.value = { ...platformContentTypes.value, [platformId]: contentType };
 };
 
+// Per-platform media assignment (empty array means "applies to every media item").
+const platformMediaIds = ref<Record<string, string[]>>(
+    Object.fromEntries(post.value.post_platforms.map((pp) => [pp.id, pp.media_ids ?? []])),
+);
+
+const updatePlatformMediaIds = (platformId: string, mediaIds: string[]) => {
+    platformMediaIds.value = { ...platformMediaIds.value, [platformId]: mediaIds };
+};
+
 const {
     platformLimits,
     mediaIssues,
@@ -265,6 +275,7 @@ const getSubmitData = () => {
             id: pp.id,
             content_type: platformContentTypes.value[pp.id] ?? pp.content_type,
             meta: platformMeta.value[pp.id] ?? pp.meta ?? {},
+            media_ids: platformMediaIds.value[pp.id] ?? pp.media_ids ?? [],
         }));
 
     return {
@@ -312,7 +323,7 @@ const triggerAutosave = () => {
     }
 };
 
-watch([content, media, selectedPlatformIds, scheduledDateTime, selectedLabelIds, platformMeta, platformContentTypes], triggerAutosave, { deep: true });
+watch([content, media, selectedPlatformIds, scheduledDateTime, selectedLabelIds, platformMeta, platformContentTypes, platformMediaIds], triggerAutosave, { deep: true });
 
 onUnmounted(() => {
     debouncedSave.cancel();
@@ -457,6 +468,7 @@ usePostEcho(post.value.id, '.post.comment.created', (e: any) => {
                             :selected-platform-ids="selectedPlatformIds"
                             :platform-meta="platformMeta"
                             :platform-content-types="platformContentTypes"
+                            :platform-media-ids="platformMediaIds"
                             :platform-issues="platformIssues"
                             :platform-configs="platformConfigs"
                             :labels="labels"
@@ -471,6 +483,7 @@ usePostEcho(post.value.id, '.post.comment.created', (e: any) => {
                             @toggle-label="toggleLabel"
                             @update:platform-meta="updatePlatformMeta"
                             @update:platform-content-type="updatePlatformContentType"
+                            @update:platform-media-ids="updatePlatformMediaIds"
                         />
                     </div>
                 </div>
diff --git a/resources/js/types/channel.ts b/resources/js/types/channel.ts
index d9aafcbbc..57603b273 100644
--- a/resources/js/types/channel.ts
+++ b/resources/js/types/channel.ts
@@ -31,6 +31,8 @@ export interface Channel {
     socialAccount: ChannelAccount | null;
     contentType: string;
     meta: Record<string, any>;
+    /** Media item ids scoped to this channel. Empty means "applies to every post media item". */
+    mediaIds: string[];
     issue?: string | null;
     issueDocsUrl?: string | null;
     status?: string | null;
diff --git a/tests/Browser/MediaAssignmentGridTest.php b/tests/Browser/MediaAssignmentGridTest.php
new file mode 100644
index 000000000..21cdc08ad
--- /dev/null
+++ b/tests/Browser/MediaAssignmentGridTest.php
@@ -0,0 +1,143 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Enums\SocialAccount\Platform;
+use App\Enums\UserWorkspace\Role;
+use App\Models\Post;
+use App\Models\PostPlatform;
+use App\Models\SocialAccount;
+use App\Models\User;
+use App\Models\Workspace;
+
+/**
+ * A post with 3 media items and one enabled LinkedIn channel. `media_ids` on
+ * the seeded PostPlatform starts empty, which MediaAssignmentGrid reads as
+ * "unscoped, every item included" (see isIncluded()), so all three tiles
+ * render as selected before any toggle happens.
+ */
+function seedMediaAssignmentGridPost(): PostPlatform
+{
+    $user = User::factory()->create();
+    $workspace = Workspace::factory()->create(['user_id' => $user->id]);
+    $workspace->members()->attach($user->id, ['role' => Role::Member->value]);
+    $user->update(['current_workspace_id' => $workspace->id]);
+
+    $account = SocialAccount::factory()->create([
+        'workspace_id' => $workspace->id,
+        'platform' => Platform::LinkedIn,
+    ]);
+
+    $mediaItem = fn (string $id) => [
+        'id' => $id,
+        'type' => 'image',
+        'mime_type' => 'image/png',
+        'path' => "uploads/{$id}.png",
+        'url' => 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==',
+        'size' => 128,
+    ];
+
+    $post = Post::factory()->create([
+        'workspace_id' => $workspace->id,
+        'user_id' => $user->id,
+        'content' => 'three media items',
+        'media' => [$mediaItem('m1'), $mediaItem('m2'), $mediaItem('m3')],
+    ]);
+
+    $postPlatform = PostPlatform::factory()->create([
+        'post_id' => $post->id,
+        'social_account_id' => $account->id,
+        'platform' => Platform::LinkedIn,
+    ]);
+
+    test()->actingAs($user);
+
+    return $postPlatform;
+}
+
+/**
+ * Poll browser-side until the testid element has laid out (width/height > 0).
+ * Pest browser assertions do not auto-wait on SPA paint.
+ */
+function waitForMediaAssignmentTestId(mixed $page, string $testId): void
+{
+    $page->script(<<<JS
+        (async () => {
+            const sel = '[data-testid="{$testId}"]';
+            for (let i = 0; i < 100; i++) {
+                const el = document.querySelector(sel);
+                if (el && el.getBoundingClientRect().height > 0) return;
+                await new Promise((r) => setTimeout(r, 50));
+            }
+        })();
+    JS);
+}
+
+/**
+ * Poll browser-side until the testid element is removed from the DOM (used
+ * after a toggle-off click, where the "-on" badge unmounts).
+ */
+function waitForMediaAssignmentGone(mixed $page, string $testId): void
+{
+    $page->script(<<<JS
+        (async () => {
+            const sel = '[data-testid="{$testId}"]';
+            for (let i = 0; i < 100; i++) {
+                if (! document.querySelector(sel)) return;
+                await new Promise((r) => setTimeout(r, 50));
+            }
+        })();
+    JS);
+}
+
+/**
+ * A fixed dwell so a click that is expected to be a no-op (the guarded third
+ * toggle) still gives Vue's reactivity a chance to flush before asserting
+ * nothing changed. Unlike waitForMediaAssignmentGone(), there is no DOM
+ * transition to poll for when the click is correctly rejected.
+ */
+function settleMediaAssignmentGrid(mixed $page): void
+{
+    $page->script(<<<'JS'
+        (async () => {
+            await new Promise((r) => setTimeout(r, 300));
+        })();
+    JS);
+}
+
+test('the last remaining media item for a channel cannot be toggled off', function () {
+    $postPlatform = seedMediaAssignmentGridPost();
+
+    $page = visit(route('app.posts.edit', $postPlatform->post));
+    waitForMediaAssignmentTestId($page, 'media-assignment-m1-on');
+
+    // All three items start unscoped/included.
+    $page->assertPresent('@media-assignment-m1-on')
+        ->assertPresent('@media-assignment-m2-on')
+        ->assertPresent('@media-assignment-m3-on');
+
+    $page->click('@media-assignment-m1');
+    waitForMediaAssignmentGone($page, 'media-assignment-m1-on');
+
+    $page->assertMissing('@media-assignment-m1-on')
+        ->assertPresent('@media-assignment-m2-on')
+        ->assertPresent('@media-assignment-m3-on');
+
+    $page->click('@media-assignment-m2');
+    waitForMediaAssignmentGone($page, 'media-assignment-m2-on');
+
+    $page->assertMissing('@media-assignment-m1-on')
+        ->assertMissing('@media-assignment-m2-on')
+        ->assertPresent('@media-assignment-m3-on');
+
+    // m3 is the last remaining selected item: the toggle guard must refuse
+    // to clear it, rather than silently flipping the selection back to
+    // "unscoped" (which would re-include m1 and m2 too).
+    $page->click('@media-assignment-m3');
+    settleMediaAssignmentGrid($page);
+
+    $page->assertPresent('@media-assignment-m3-on')
+        ->assertMissing('@media-assignment-m1-on')
+        ->assertMissing('@media-assignment-m2-on')
+        ->assertNoJavaScriptErrors();
+});
diff --git a/tests/Feature/PostControllerTest.php b/tests/Feature/PostControllerTest.php
index e68ea13e5..e2cfa30f2 100644
--- a/tests/Feature/PostControllerTest.php
+++ b/tests/Feature/PostControllerTest.php
@@ -9,6 +9,7 @@
 use App\Enums\SocialAccount\Platform;
 use App\Enums\UserWorkspace\Role;
 use App\Jobs\PublishPost;
+use App\Models\Media;
 use App\Models\Post;
 use App\Models\PostPlatform;
 use App\Models\SocialAccount;
@@ -374,6 +375,40 @@
         );
 });
 
+test('edit exposes media_ids for each platform, scoped or not', function () {
+    $post = Post::factory()->create([
+        'workspace_id' => $this->workspace->id,
+        'user_id' => $this->user->id,
+        'status' => PostStatus::Draft,
+    ]);
+
+    $asset = Media::factory()->assets()->create([
+        'mediable_type' => (new Workspace)->getMorphClass(),
+        'mediable_id' => $this->workspace->id,
+    ]);
+
+    $scopedPlatform = PostPlatform::factory()->create([
+        'post_id' => $post->id,
+        'social_account_id' => $this->socialAccount->id,
+    ]);
+    $scopedPlatform->media()->sync([$asset->id]);
+
+    $secondAccount = SocialAccount::factory()->create(['workspace_id' => $this->workspace->id]);
+    $unscopedPlatform = PostPlatform::factory()->create([
+        'post_id' => $post->id,
+        'social_account_id' => $secondAccount->id,
+    ]);
+
+    $response = $this->actingAs($this->user)
+        ->get(route('app.posts.edit', $post))
+        ->assertOk();
+
+    $platforms = collect($response->original->getData()['page']['props']['post']['post_platforms']);
+
+    expect($platforms->firstWhere('id', $scopedPlatform->id)['media_ids'])->toBe([$asset->id])
+        ->and($platforms->firstWhere('id', $unscopedPlatform->id)['media_ids'])->toBe([]);
+});
+
 test('edit post returns 404 for post from different workspace', function () {
     $otherWorkspace = Workspace::factory()->create();
     $post = Post::factory()->create([
diff --git a/tests/Feature/UpdatePostRequestTest.php b/tests/Feature/UpdatePostRequestTest.php
index 8c96b7b37..3f209a26c 100644
--- a/tests/Feature/UpdatePostRequestTest.php
+++ b/tests/Feature/UpdatePostRequestTest.php
@@ -865,3 +865,115 @@
             'platforms.0.meta.link' => __('posts.form.pinterest.link_invalid'),
         ]);
 });
+
+test('saving a platform with media_ids scopes it to only those media items', function () {
+    $imageOne = Media::factory()->assets()->create([
+        'mediable_type' => (new Workspace)->getMorphClass(),
+        'mediable_id' => $this->workspace->id,
+    ]);
+    $imageTwo = Media::factory()->assets()->create([
+        'mediable_type' => (new Workspace)->getMorphClass(),
+        'mediable_id' => $this->workspace->id,
+    ]);
+
+    $mediaPayload = [
+        ['id' => $imageOne->id, 'path' => $imageOne->path, 'url' => 'https://example.com/one.jpg', 'type' => 'image'],
+        ['id' => $imageTwo->id, 'path' => $imageTwo->path, 'url' => 'https://example.com/two.jpg', 'type' => 'image'],
+    ];
+
+    $this->actingAs($this->user)
+        ->put(route('app.posts.update', $this->post), [
+            'status' => Status::Draft->value,
+            'media' => $mediaPayload,
+            'platforms' => [[
+                'id' => $this->postPlatform->id,
+                'content_type' => ContentType::TikTokVideo->value,
+                'meta' => [],
+                'media_ids' => [$imageOne->id],
+            ]],
+        ])
+        ->assertSessionDoesntHaveErrors();
+
+    $scoped = $this->postPlatform->fresh()->scopedMediaItems();
+
+    expect($scoped)->toHaveCount(1)
+        ->and($scoped->first()->id)->toBe($imageOne->id);
+});
+
+test('a media_id not on this request is rejected', function () {
+    $foreignAsset = Media::factory()->assets()->create([
+        'mediable_type' => (new Workspace)->getMorphClass(),
+        'mediable_id' => $this->workspace->id,
+    ]);
+
+    $this->actingAs($this->user)
+        ->put(route('app.posts.update', $this->post), [
+            'status' => Status::Draft->value,
+            'media' => $this->mediaPayload,
+            'platforms' => [[
+                'id' => $this->postPlatform->id,
+                'content_type' => ContentType::TikTokVideo->value,
+                'meta' => [],
+                'media_ids' => [$foreignAsset->id],
+            ]],
+        ])
+        ->assertSessionHasErrors('platforms.0.media_ids.0');
+});
+
+test('clearing media_ids with an empty array removes the scoping', function () {
+    $imageOne = Media::factory()->assets()->create([
+        'mediable_type' => (new Workspace)->getMorphClass(),
+        'mediable_id' => $this->workspace->id,
+    ]);
+    $imageTwo = Media::factory()->assets()->create([
+        'mediable_type' => (new Workspace)->getMorphClass(),
+        'mediable_id' => $this->workspace->id,
+    ]);
+    $this->postPlatform->media()->sync([$imageOne->id]);
+
+    $mediaPayload = [
+        ['id' => $imageOne->id, 'path' => $imageOne->path, 'url' => 'https://example.com/one.jpg', 'type' => 'image'],
+        ['id' => $imageTwo->id, 'path' => $imageTwo->path, 'url' => 'https://example.com/two.jpg', 'type' => 'image'],
+    ];
+
+    $this->actingAs($this->user)
+        ->put(route('app.posts.update', $this->post), [
+            'status' => Status::Draft->value,
+            'media' => $mediaPayload,
+            'platforms' => [[
+                'id' => $this->postPlatform->id,
+                'content_type' => ContentType::TikTokVideo->value,
+                'meta' => [],
+                'media_ids' => [],
+            ]],
+        ])
+        ->assertSessionDoesntHaveErrors();
+
+    expect($this->postPlatform->fresh()->scopedMediaItems())->toHaveCount(2);
+});
+
+test('omitting media_ids leaves existing scoping untouched', function () {
+    $imageOne = Media::factory()->assets()->create([
+        'mediable_type' => (new Workspace)->getMorphClass(),
+        'mediable_id' => $this->workspace->id,
+    ]);
+    $this->post->update(['media' => [
+        ['id' => $imageOne->id, 'path' => $imageOne->path, 'url' => 'https://example.com/one.jpg', 'type' => 'image'],
+    ]]);
+    $this->postPlatform->media()->sync([$imageOne->id]);
+
+    $this->actingAs($this->user)
+        ->put(route('app.posts.update', $this->post), [
+            'status' => Status::Draft->value,
+            'platforms' => [[
+                'id' => $this->postPlatform->id,
+                'content_type' => ContentType::TikTokVideo->value,
+                'meta' => [],
+            ]],
+        ])
+        ->assertSessionDoesntHaveErrors();
+
+    $scoped = $this->postPlatform->fresh()->scopedMediaItems();
+    expect($scoped)->toHaveCount(1)
+        ->and($scoped->first()->id)->toBe($imageOne->id);
+});