diff --git a/functions.php b/functions.php
index 7ca7dcf..345946e 100644
--- a/functions.php
+++ b/functions.php
@@ -131,7 +131,7 @@ function themeInit($archive){
 }
 
 function showThumb($obj,$size=null,$link=false){
-    preg_match_all( "/<[img|IMG].*?src=[\'|\"](.*?)[\'|\"].*?[\/]?>/", $obj->content, $matches );
+    preg_match_all( '/<img\s+[^>]*src=["\']([^"\']*)["\'][^>]*>/i', $obj->content, $matches );
     $thumb = '';
     $options = Typecho_Widget::widget('Widget_Options');
     $attach = $obj->attachments(1)->attachment;
@@ -325,4 +325,4 @@ function compressHtml($html_source) {
         $compress .= $c;
     }
     return $compress;
-}
\ No newline at end of file
+}