Ticket #17262: 17262.2.diff

wp-includes/post.php

@@ -4246 +4246 @@
  */
 function wp_get_attachment_thumb_file( $post_id = 0 ) {
         $post_id = (int) $post_id;
-        if ( !$post = get_post( $post_id ) )
+        if ( ! $post = get_post( $post_id ) )
                 return false;
-        if ( !is_array( $imagedata = wp_get_attachment_metadata( $post->ID ) ) )
+        if ( ! is_array( $imagedata = wp_get_attachment_metadata( $post->ID ) ) )
                 return false;
 
         $file = get_attached_file( $post->ID );
 
-        if ( !empty($imagedata['thumb']) && ($thumbfile = str_replace(basename($file), $imagedata['thumb'], $file)) && file_exists($thumbfile) )
+        if ( ! empty( $imagedata['sizes']['thumbnail']['file'] )
+                && ( $thumbfile = str_replace( basename( $file ), $imagedata['sizes']['thumbnail']['file'], $file ) )
+                && file_exists( $thumbfile ) )
                 return apply_filters( 'wp_get_attachment_thumb_file', $thumbfile, $post->ID );
         return false;
 }