diff --git a/getPreview.php b/getPreview.php
index bd27ef2..2f6d532 100644
--- a/getPreview.php
+++ b/getPreview.php
@@ -81,11 +81,13 @@ function getFullNumberString($number)
     return $number;
 }
 
+$imageDataHash  =   "";
+
 while(true)
 {
-    $streamInfo = getStreamInfo($globalData['Channel']);
-    $previewURL = getPreviewURL($streamInfo, "1920", "1080");
-    
+    $streamInfo     = getStreamInfo($globalData['Channel']);
+    $previewURL     = getPreviewURL($streamInfo, "1920", "1080");
+
     if($previewURL == "")
     {
         print_r($globalData);
@@ -94,13 +96,20 @@ while(true)
         echo "URL == ".$previewURL."\n";
         die("fatal error");
     }
-        
 
     $imageFileName = $globalData['Folder'].getFullNumberString((getFileCountInFolder() + 1)).".".getFileExtention($previewURL);
 
     echo "Copy preview url '".$previewURL."' to '".$imageFileName."' ...";
-    file_put_contents($imageFileName, file_get_contents($previewURL, false, $globalData['sslContext']));
-    echo "done\n";
+
+    $imageRawData   =   file_get_contents($previewURL, false, $globalData['sslContext']);
+    
+    if(md5($imageRawData) != $imageDataHash)
+    {
+        file_put_contents($imageFileName, $imageRawData);
+        echo "done\n";
+    }else{
+        echo "canceled\n";
+    }
 
     $imageRawData = "";
     system("ffmpeg -f image2 -framerate 3 -i /data/images/%07d.jpg -r 25 -vcodec libx264 -y /data/images/video.mp4");