WebP image thumbnails don't show up in Thunar. They appear as RIFF audio. When I click on them I can see them as images in my image viewer. But I'd like to see the thumbnails as well. I've read elsewhere that I may have to play around with mimetypes, or contact the Thunar developers. I'm hoping there's an easier solution.
Unfortunately, it doesn't look like tumbler (the Xfce thumbnailing service) supports webp. You'll probably need to create an enhancement request (https://bugzilla.xfce.org/buglist.cgi?c … lution=---) or contact the developers on the xfce4-dev mailing list.