Answer by Bastian Gebhardt for How to add WebP support to Eye of GNOME?

I found this OMG! Ubuntu! article: How to Add WebP Support to Ubuntu 22.04 LTS

Just add the ppa:helkaluin/webp-pixbuf-loader PPA:

sudo add-apt-repository ppa:helkaluin/webp-pixbuf-loader

Then install webp-pixbuf-loader:

sudo apt install webp-pixbuf-loader

and you're done. Works for me on Ubuntu 20.04.