diff --git a/get_peertube_videos/get_peertube_videos.py b/get_peertube_videos/get_peertube_videos.py
index d608fc9..2afeb1a 100644
--- a/get_peertube_videos/get_peertube_videos.py
+++ b/get_peertube_videos/get_peertube_videos.py
@@ -173,6 +173,8 @@ class GetPeertubeVideos:
             thumb_file,
             video_file
         )
+        split_filename = video_file.split('.')
+        file_extension = split_filename[len(split_filename)-1]
         result = subprocess.run(
                 [
                     'ffmpeg',
@@ -181,7 +183,7 @@ class GetPeertubeVideos:
                     '-map', '1',
                     '-map', '0',
                     '-c', 'copy',
-                    '-disposition:0', 'attached_pic', f"{video_file}_with_thumb"
+                    '-disposition:0', 'attached_pic', f"{video_file}_with_thumb.{file_extension}"
                 ],
                 capture_output=True,
                 check=False
@@ -194,7 +196,7 @@ class GetPeertubeVideos:
                 result.stderr
             )
         os.remove(video_file)
-        os.rename(f"{video_file}_with_thumb", video_file)
+        os.rename(f"{video_file}_with_thumb.{file_extension}", video_file)
 
     def _write_downloaded_items(self):
         with open(self.config['downloaded_database'], 'w', encoding='utf-8') as db_file: