Thank you. A clickbait result came up during a search and the thumbnail was a big close up of something I found very disturbing. I searched for a way to hide thumbnail images and found this. It works. I especially like that it hides them not only in search results but also recommended videos. So, if that horrid clickbait video comes up I still don't have to see the image.

The only issue and it's a minor one is hide unless hovering doesn't seem to work. When I tried that option the thumbnails were just visible. For peace of mind I'm choosing to just hide thumbnails all the time.