-        if not opts.addmetadata:
-            postprocessors.append({'key': 'FFmpegAudioFix'})
-        postprocessors.append({'key': 'AtomicParsley'})
+        already_have_thumbnail = opts.writethumbnail or opts.write_all_thumbnails
+        postprocessors.append({
+            'key': 'EmbedThumbnail',
+            'already_have_thumbnail': already_have_thumbnail
+        })
+        if not already_have_thumbnail:
+            opts.writethumbnail = True