I did a small trial of AVIF (using the AVIF plugin for pillow) with high quality photographs and got much worse results than WEBP. (Much bigger file that looked much worse.)

It could be my encoder sucks, could be I didn’t pick the right settings (command line opts look like the engineer’s console on the original 747). Most of the demos I have seen online with AVIF images are highly compressed images that look awful on close inspection. Maybe you can accept that for video but I can’t for my photographs.

I was disappointed.