get_part_content() -> get_part_body()

program/steps/mail/get.inc

@@ -85,7 +85,7 @@ else if ($_GET['_thumb']) {
         // render thumbnail image if not done yet
         if (!is_file($cache_file)) {
             if ($fp = fopen(($orig_name = $cache_basename . '.orig.' . $ext), 'w')) {
-                $MESSAGE->get_part_content($part->mime_id, $fp);
+                $MESSAGE->get_part_body($part->mime_id, false, 0, $fp);
                 fclose($fp);
 
                 $image = new rcube_image($orig_name);