Ticket #17262: 17262.diff

post.php

@@ -3882 +3882 @@
 
         $file = get_attached_file( $post->ID );
 
-        if ( !empty($imagedata['thumb']) && ($thumbfile = str_replace(basename($file), $imagedata['thumb'], $file)) && file_exists($thumbfile) )
+        if ( !empty($imagedata['thumbnail']) && ($thumbfile = str_replace(basename($file), $imagedata['thumbnail'], $file)) && file_exists($thumbfile) )
                 return apply_filters( 'wp_get_attachment_thumb_file', $thumbfile, $post->ID );
         return false;
 }