diff --git a/src/include/image_is_resizable.php b/src/include/image_is_resizable.php
index 526db23..f0ea2ea 100644
--- a/src/include/image_is_resizable.php
+++ b/src/include/image_is_resizable.php
@@ -5,11 +5,11 @@
   if(file_exists($filename))
   {
     $image = Helper::ImageCreateFromGeneral($filename);
-    if(is_resource($image))
+    if(is_resource($image) || $image instanceof \GdImage)
     {
       ImageDestroy($image);
       $result = 1;
     }
   }
   print $result;
-?>
\ No newline at end of file
+?>