diff --git a/getPreview.php b/getPreview.php
index 2f6d532..1f72a2b 100644
--- a/getPreview.php
+++ b/getPreview.php
@@ -105,6 +105,7 @@ while(true)
     
     if(md5($imageRawData) != $imageDataHash)
     {
+        $imageDataHash  =   md5($imageRawData);
         file_put_contents($imageFileName, $imageRawData);
         echo "done\n";
     }else{