To restore animated thumbnail previews. Requires inline video previews to be disabled in your YouTube user settings (Go to https://www.youtube.com/account_playback and set "video previews" to disabled). Not Greasemonkey compatible. v5 Add new method for getting an_webp GIF-style thumbs when not available in YT's new homepage UI or subscription page UI.
< Feedback on Restore animated thumbnail previews - youtube.com
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.