diff --git a/studio-ui/ui/app/src/components/FormsEngine/controls/ImagePicker.tsx b/studio-ui/ui/app/src/components/FormsEngine/controls/ImagePicker.tsx
index 8652e4c7c..e6d0c7bee 100644
--- a/studio-ui/ui/app/src/components/FormsEngine/controls/ImagePicker.tsx
+++ b/studio-ui/ui/app/src/components/FormsEngine/controls/ImagePicker.tsx
@@ -14,7 +14,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-import React, { useEffect, useState } from 'react';
+import React, { useEffect, useRef, useState } from 'react';
 import Box from '@mui/material/Box';
 import Card from '@mui/material/Card';
 import CardContent from '@mui/material/CardContent';
@@ -31,16 +31,22 @@ import { listItemIconClasses } from '@mui/material/ListItemIcon';
 import Menu from '@mui/material/Menu';
 import { useImageInfo } from '../../../hooks/useImageInfo';
 import { svgIconClasses } from '@mui/material/SvgIcon';
-import { ensureSingleSlash } from '../../../utils/string';
+import { isExternalMediaUrl, resolveMediaUrl } from '../../../utils/string';
 import { useDispatch } from 'react-redux';
 import Tooltip from '@mui/material/Tooltip';
-import { downloadMedia, getImageRestrictionMessages, showImageCropDialog } from '../lib/controlHelpers';
+import Alert from '@mui/material/Alert';
+import {
+	downloadMedia,
+	getImageRestrictionMessages,
+	ImageRestrictionSubtitle,
+	showImageCropDialog
+} from '../lib/controlHelpers';
 import type { ImageRestrictions } from '../../ImageEditorDialog/types';
 import Skeleton from '@mui/material/Skeleton';
 import { nnou, nou } from '../../../utils/object';
 import { validateImageRestrictions } from '../../../utils/content';
 import GroupedDataSourceActionMenuItems from '../components/GroupedDataSourceActionMenuItems';
-import type { DataSourceSelection } from '../dataSources/types';
+import type { DataSourceAssetSelection, DataSourceSelection } from '../dataSources/types';
 import { showSystemNotification } from '../../../state/actions/system';
 import { EmptyState } from '../../EmptyState';
 
@@ -68,9 +74,9 @@ export function ImagePicker(props: ImagePickerProps) {
 	// endregion
 
 	const value = nnou(valueProp) ? valueProp : (defaultValue ?? '');
-	const { imageInfo, isFetchingDimensions, isFetchingMetadata, errorDimensions, errorMetadata } = useImageInfo(
-		value ? ensureSingleSlash(`${guestBase}${value}`) : ''
-	);
+	const mediaUrl = value ? resolveMediaUrl(guestBase, value) : '';
+	const { imageInfo, isFetchingDimensions, isFetchingMetadata, errorDimensions, errorMetadata } =
+		useImageInfo(mediaUrl);
 	const hasValue = Boolean(value);
 	const actions = dataSources?.actions ?? [];
 	const dataSourcesLoading = dataSources?.status === 'loading';
@@ -78,6 +84,8 @@ export function ImagePicker(props: ImagePickerProps) {
 	const actionsReady = Boolean(dataSources?.context) && actions.length > 0 && !dataSourcesLoading;
 	const [anchorEl, setAnchorEl] = useState<HTMLElement | null>(null);
 	const [addMenuOpen, setAddMenuOpen] = useState(false);
+	const [rejectedExternalUrl, setRejectedExternalUrl] = useState<string | null>(null);
+	const selectionRequestRef = useRef(0);
 
 	useEffect(() => {
 		// If there's a default value and no value has been set yet, set it as the value.
@@ -88,6 +96,7 @@ export function ImagePicker(props: ImagePickerProps) {
 
 	const imageRestrictionMessages = getImageRestrictionMessages(restrictions);
 	const applySelection = (selection: DataSourceSelection | DataSourceSelection[] | null) => {
+		const requestId = ++selectionRequestRef.current;
 		const selected = Array.isArray(selection) ? selection[0] : selection;
 		const path =
 			selected?.kind === 'asset' && typeof selected.relativeUrl === 'string'
@@ -96,9 +105,17 @@ export function ImagePicker(props: ImagePickerProps) {
 					? selected.path
 					: undefined;
 		if (!path) return;
-		validateImageRestrictions(path, restrictions)
+		setRejectedExternalUrl(null);
+		validateImageRestrictions(path, restrictions, (selected as DataSourceAssetSelection).mimeType)
 			.then((meetsRestrictions) => {
-				if (!meetsRestrictions) {
+				if (requestId !== selectionRequestRef.current) return;
+				if (meetsRestrictions) {
+					setValue(path);
+				} else if (isExternalMediaUrl(path)) {
+					// Cropping requires writing the result to a site path, which isn't possible for an external URL. The
+					// crop would be discarded and the field would keep the offending URL, so reject the selection instead.
+					setRejectedExternalUrl(path);
+				} else {
 					showImageCropDialog({
 						dispatch,
 						path,
@@ -108,11 +125,10 @@ export function ImagePicker(props: ImagePickerProps) {
 						writeContent: true,
 						onCrop: (_blob: Blob, newPath: string) => setValue(newPath ?? path)
 					});
-				} else {
-					setValue(path);
 				}
 			})
 			.catch(() => {
+				if (requestId !== selectionRequestRef.current) return;
 				dispatch(
 					showSystemNotification({
 						message: formatMessage({ defaultMessage: 'Unable to validate image restrictions.' })
@@ -132,6 +148,8 @@ export function ImagePicker(props: ImagePickerProps) {
 	) : null;
 
 	const handleRemoveImage = () => {
+		selectionRequestRef.current += 1;
+		setRejectedExternalUrl(null);
 		setValue(null);
 	};
 
@@ -147,15 +165,25 @@ export function ImagePicker(props: ImagePickerProps) {
 			>
 				{actionMenuItems}
 			</Menu>
-			<FormsEngineField field={field}>
+			<FormsEngineField field={field} isValid={rejectedExternalUrl ? false : undefined}>
+				{rejectedExternalUrl && (
+					<Alert
+						severity="error"
+						variant="outlined"
+						sx={{ border: 'none' }}
+						onClose={() => setRejectedExternalUrl(null)}
+					>
+						<FormattedMessage
+							defaultMessage="The image at {url} was not applied."
+							values={{ url: rejectedExternalUrl }}
+						/>{' '}
+						<ImageRestrictionSubtitle restrictions={restrictions} />{' '}
+						<FormattedMessage defaultMessage="External images can't be cropped. Select an image that meets the requirements." />
+					</Alert>
+				)}
 				{hasValue ? (
 					<Card sx={{ display: 'flex' }}>
-						<CardMedia
-							component="img"
-							sx={{ width: '40%' }}
-							image={`${guestBase}${value}`}
-							alt="Live from space album cover"
-						/>
+						<CardMedia component="img" sx={{ width: '40%' }} image={mediaUrl} alt="" />
 						<Box sx={{ display: 'flex', flexDirection: 'column' }}>
 							<CardContent sx={{ flex: '1 0 auto' }}>
 								<Typography component="div" variant="body1" marginBottom={1}>
diff --git a/studio-ui/ui/app/src/components/FormsEngine/controls/VideoPicker.tsx b/studio-ui/ui/app/src/components/FormsEngine/controls/VideoPicker.tsx
index a9dea6299..be4bd08ea 100644
--- a/studio-ui/ui/app/src/components/FormsEngine/controls/VideoPicker.tsx
+++ b/studio-ui/ui/app/src/components/FormsEngine/controls/VideoPicker.tsx
@@ -29,7 +29,7 @@ import Typography from '@mui/material/Typography';
 import IconButton from '@mui/material/IconButton';
 import { DeleteOutlined, DownloadOutlined, EditOutlined } from '@mui/icons-material';
 import { svgIconClasses } from '@mui/material';
-import { ensureSingleSlash } from '../../../utils/string';
+import { resolveMediaUrl } from '../../../utils/string';
 import useVideoInfo from '../../../hooks/useVideoInfo';
 import Skeleton from '@mui/material/Skeleton';
 import { downloadMedia } from '../lib/controlHelpers';
@@ -47,13 +47,11 @@ export interface VideoPickerProps extends ControlProps {
 export function VideoPicker(props: VideoPickerProps) {
 	const { field, value, setValue, readonly: formReadonly, dataSources } = props;
 	const { guestBase } = useEnv();
-	// TODO: For testing, by using 3000 as the guestBase both the fetch in `useImageInfo` and the download functionality will work
-	// const guestBase = 'http://localhost:3000';
 	const hasValue = Boolean(value);
+	const mediaUrl = value ? resolveMediaUrl(guestBase, value) : '';
 	const { formatMessage } = useIntl();
-	const { videoInfo, isFetchingMetadata, isFetchingDimensions, errorDimensions, errorMetadata } = useVideoInfo(
-		value ? ensureSingleSlash(`${guestBase}${value}`) : ''
-	);
+	const { videoInfo, isFetchingMetadata, isFetchingDimensions, errorDimensions, errorMetadata } =
+		useVideoInfo(mediaUrl);
 	const [anchorEl, setAnchorEl] = React.useState<null | HTMLElement>(null);
 	const [addMenuOpen, setAddMenuOpen] = useState(false);
 
@@ -99,7 +97,7 @@ export function VideoPicker(props: VideoPickerProps) {
 			<FormsEngineField field={field}>
 				{hasValue ? (
 					<Card sx={{ display: 'flex' }}>
-						<CardMedia component="video" sx={{ width: '40%' }} image={ensureSingleSlash(`${guestBase}${value}`)} />
+						<CardMedia component="video" sx={{ width: '40%' }} image={mediaUrl} />
 						<Box sx={{ display: 'flex', flexDirection: 'column' }}>
 							<CardContent sx={{ flex: '1 0 auto' }}>
 								<Typography component="div" variant="body1" marginBottom={1}>
diff --git a/studio-ui/ui/app/src/components/FormsEngine/lib/controlHelpers.tsx b/studio-ui/ui/app/src/components/FormsEngine/lib/controlHelpers.tsx
index 350bd17e6..c52f80c64 100644
--- a/studio-ui/ui/app/src/components/FormsEngine/lib/controlHelpers.tsx
+++ b/studio-ui/ui/app/src/components/FormsEngine/lib/controlHelpers.tsx
@@ -29,7 +29,7 @@ import ContentType from '../../../models/ContentType';
 import FormsEngineField from '../components/FormsEngineField';
 import { FormsEngineAtoms, ItemContext, ItemMetaContext, StableGlobalContext } from './formsEngineContext';
 import { getFileNameFromPath } from '../../../utils/path';
-import { ensureSingleSlash } from '../../../utils/string';
+import { isExternalMediaUrl, resolveMediaUrl } from '../../../utils/string';
 import { Dispatch as ReduxDispatch } from 'redux';
 import { BrowseFilesDialogProps } from '../../BrowseFilesDialog';
 import { nanoid } from 'nanoid';
@@ -208,7 +208,7 @@ export function renderFieldControl(
  * */
 export function downloadMedia(base: string, url: string) {
 	const link = document.createElement('a');
-	link.href = ensureSingleSlash(`${base}${url}`);
+	link.href = resolveMediaUrl(base, url);
 	link.download = getFileNameFromPath(url); // Extracts the file name from the URL
 	document.body.appendChild(link);
 	link.click();
@@ -362,6 +362,8 @@ export const showImageCropDialog = ({
 	onCrop: (blob: Blob, newPath?: string) => void;
 }): void => {
 	const dialogId = nanoid();
+	// Remote/absolute URLs load as `src` in the editor; writing cropped content back requires a site path.
+	const canWriteContent = writeContent !== false && !isExternalMediaUrl(path);
 	dispatch(
 		pushDialog({
 			id: dialogId,
@@ -371,7 +373,7 @@ export const showImageCropDialog = ({
 				mimeType,
 				subtitle: restrictions ? <ImageRestrictionSubtitle restrictions={restrictions} /> : undefined,
 				restrictions,
-				writeContent,
+				writeContent: canWriteContent,
 				onCrop: (blob: Blob, newPath: string) => {
 					dispatch(popDialog({ id: dialogId }));
 					onCrop?.(blob, newPath);
diff --git a/studio-ui/ui/app/src/utils/content.ts b/studio-ui/ui/app/src/utils/content.ts
index da1af7cee..53c7aaacc 100644
--- a/studio-ui/ui/app/src/utils/content.ts
+++ b/studio-ui/ui/app/src/utils/content.ts
@@ -21,7 +21,7 @@ import { ContentType, ContentTypeField } from '../models/ContentType';
 import LookupTable from '../models/LookupTable';
 import ContentInstance, { ContentInstanceBase } from '../models/ContentInstance';
 import { deserialize, fromString, getInnerHtml, getInnerHtmlNumber, serialize, wrapElementInAuxDocument } from './xml';
-import { fileNameFromPath, replaceAccentedVowels, unescapeHTML } from './string';
+import { fileNameFromPath, isExternalMediaUrl, replaceAccentedVowels, unescapeHTML } from './string';
 import { getRootPath, isRootPath, withIndex, withoutIndex } from './path';
 import { isFolder, isNavigable, isPreviewable } from '../components/PathNavigator/utils';
 import {
@@ -1208,8 +1208,15 @@ function doesImageMeetSizeRestrictions(file: HTMLImageElement, restrictions?: Im
  * @param restrictions - Optional size restrictions to validate the image against.
  * @returns Promise that resolves to true if the image meets the restrictions or no restrictions are provided, false otherwise.
  * */
-export function validateImageRestrictions(path: string, restrictions?: ImageRestrictions): Promise<boolean> {
-	if (!restrictions || (!isImage(path) && !isBlobUrl(path) && !path.startsWith('data:image/'))) {
+export function validateImageRestrictions(
+	path: string,
+	restrictions?: ImageRestrictions,
+	mimeType?: string
+): Promise<boolean> {
+	// External URLs (including blob/data URLs) may have no extension or a query string, so extension detection can't be
+	// used to rule them out. They're loaded and validated; non-images resolve as valid via the error handler below.
+	const isValidationCandidate = isImage(path) || mimeType?.startsWith('image/') || isExternalMediaUrl(path);
+	if (!restrictions || !isValidationCandidate) {
 		return Promise.resolve(true);
 	}
 	return new Promise((resolve) => {
diff --git a/studio-ui/ui/app/src/utils/string.ts b/studio-ui/ui/app/src/utils/string.ts
index f563e5e6e..6be743610 100644
--- a/studio-ui/ui/app/src/utils/string.ts
+++ b/studio-ui/ui/app/src/utils/string.ts
@@ -180,6 +180,27 @@ export function ensureSingleSlash(url: string): string {
 	return /^(http|https):\/\//g.test(url) ? url.replace(/([^:]\/)\/+/g, '$1') : url.replace(/\/+/g, '/');
 }
 
+/**
+ * True when the value is already a loadable absolute/remote media URL (http(s), data, or blob).
+ * Site-relative paths like `/static-assets/...` return false.
+ */
+export function isExternalMediaUrl(url: string): boolean {
+	if (!url) return false;
+	return /^(https?:)?\/\//i.test(url) || /^(data|blob):/i.test(url);
+}
+
+/**
+ * Resolves a media field value for preview / fetch / download.
+ * Absolute/remote URLs are returned as-is; site paths are prefixed with `guestBase` (FE1 image-picker parity).
+ */
+export function resolveMediaUrl(guestBase: string, value: string): string {
+	if (!value) return value;
+	if (isExternalMediaUrl(value)) {
+		return value;
+	}
+	return ensureSingleSlash(`${guestBase}${value}`);
+}
+
 export function getSimplifiedVersion(version: string, options: { minor?: boolean; patch?: boolean } = {}) {
 	if (!version) {
 		return version;