diff --git a/lib/filestorage/file_storage.php b/lib/filestorage/file_storage.php
index 8a4043160f1..acbd0cbec67 100644
--- a/lib/filestorage/file_storage.php
+++ b/lib/filestorage/file_storage.php
@@ -334,6 +334,9 @@ class file_storage {
         } else if ($mode === 'thumb') {
             $data = generate_image_thumbnail($tmpfilepath, 90, 90);
 
+        } else if ($mode === 'bigthumb') {
+            $data = generate_image_thumbnail($tmpfilepath, 250, 250);
+
         } else {
             throw new file_exception('storedfileproblem', 'Invalid preview mode requested');
         }