There's a new amazing app that opens WebP and other formats that I use:
https://interversehq.com/qview/download/
It's also available for Windows and Mac. As well as having PPA, RPM, Aur, etc etc.
qView is an image viewer designed to be minimal and generally fast and easy to use. It's not for everyone, but I designed it to be exactly what I wanted from an image viewer. You can see the full spiel here.
I've been using klite codecs with the built in MPC but have been slowly moving over to mpv since it runs nicer with discord and all that. For music been running my personal build of foobar. Photos I used to run picasa but between gif support, windows scaling issues, and lack of updated support, been running qview for a while now, works pretty nice as a barebones viewer.
For another light and snappy alternative, qview is killing it IMO.
The biggest reason I can't use gwenview is that if I open an image in a folder with many, I can't go to the next or previous image for a while, while gwenview (I'm guessing) examines a bunch of the adjacent files.
I also have i3 with HD4400 and preview freezes sometimes, so I installed QView( https://interversehq.com/qview/) and set as a default image viewer. It works fine for me.