It seems to be supported by all recent browsers (https://caniuse.com/?search=webp: since 2019, except Safari for macOS < 11, ~96.75% of usage of navigators) .
The screenshots page loads around 3MB of images (for a 4MB total page), it can probably be reduced.
The large/ folder goes from ~20MB to 13MB with a lossless compression.
The small/ from ~2.8MB to 2.5MB without loss.
We can decide to switch when we'll rework the website as it is related