[EmbedThumbnail] Fix for already downloaded thumbnail

yt_dlp/YoutubeDL.py

@@ -3247,6 +3247,7 @@ class YoutubeDL(object):
 
             if not self.params.get('overwrites', True) and os.path.exists(encodeFilename(thumb_filename)):
                 ret.append(suffix + thumb_ext)
+                t['filepath'] = thumb_filename
                 self.to_screen('[%s] %s: Thumbnail %sis already present' %
                                (info_dict['extractor'], info_dict['id'], thumb_display_id))
             else:

yt_dlp/options.py

@@ -1200,7 +1200,7 @@ def parseOpts(overrideArguments=None):
     postproc.add_option(
         '--embed-thumbnail',
         action='store_true', dest='embedthumbnail', default=False,
-        help='Embed thumbnail in the audio as cover art')
+        help='Embed thumbnail in the video/audio as cover art')
     postproc.add_option(
         '--no-embed-thumbnail',
         action='store_false', dest='embedthumbnail',