To restore animated thumbnail previews, requires inline previews to be disabled in your YouTube settings. Note: not Greasemonkey compatible. v2.0 adds fallback option of a still image carousel for the homepage where YouTube has changed their data structure to no longer provide an_webp animated thumbnail urls, which is affecting some users; for such users non-homepage pages are unaffected and continue to use the an_webp animated thumbs.
< 脚本Restore animated thumbnail previews - youtube.com的反馈
Thanks for the report and it's a shame that YouTube is making these breaking changes for some users, probably it will gradually roll out to affect us all. I have just released a new version that has a fall back for the homepage to show a still image carousel, which I think is better than nothing but unfortunately I can't restore the animated thumbs to the homepage without unacceptable issues affecting search history (see other comment thread).
I hope this is seen as an improvement over no animated thumbnails on the homepage, but if not it can be disabled by editing the below line or reverting to v1.0
<>const forceDisableNewHomepageMethod = false;
toconst forceDisableNewHomepageMethod = true;
Stopped working for me about a week ago. Seems to still work everywhere except the home page.