diff --git a/include/class.thread.php b/include/class.thread.php
index ef1fed5c28a1b6318e17ffb7c19234f157fb2e7a..4eaa27e94941216641cef260752bb69220b51260 100644
--- a/include/class.thread.php
+++ b/include/class.thread.php
@@ -1189,8 +1189,8 @@ class ThreadBody /* extends SplString */ {
             if ($images_before) {
                 preg_match_all('/src="cid:([\w_-]+)"/', $this->body,
                     $images_after, PREG_SET_ORDER);
-                $this->stripped_images = array_diff($images_before,
-                    $images_after);
+                $this->stripped_images = array_diff($images_before[1],
+                    $images_after[1]);
             }
         }
     }