diff --git a/src/Model/Photo.php b/src/Model/Photo.php
index 34a5acfc9f..4baef04b9b 100644
--- a/src/Model/Photo.php
+++ b/src/Model/Photo.php
@@ -690,7 +690,7 @@ class Photo extends BaseObject
 		}
 
 		$scale = intval(substr($guid, -1, 1));
-		if (empty($scale)) {
+		if (!is_numeric($scale)) {
 			return '';
 		}