When I change something like a picture and save the new version, studio uses the current version on the timeline thumbnail and in the project, but the library thumbnail is the original image. Is there any way to update the thumbnail? Thanks.

If modifications are made on the timeline, there is no way to modify thumbnail in library. Thta's the way it has been built.

...because timeline editing is non destructive to the original video(s).

I am not talking in the timeline. I made a picture in Gimp. I then needed it changed, so I went into gimp, made changes and exported it to the original file name. In Studio the changes show up in the thumbnail on the timeline, and in the actual project, but not the library.

To refresh library thumbnails you need to delete C:\Users\Yourusername\AppData\Local\Pinnacle_Studio_20\Studio\Scratch\NGThumbnails

Thanks. It worked. Pinnacle should add a button for this, maybe even a single clip button so it takes less time.