[jcupitt]

It's actually the other way around: WebP images are about the same size as JPEG encoded with mozjpeg -- compression is no better. WebP does have advantages for images with transparency. Google effectively abandoned webp more than five years ago now and began work on webp2. But they've now abandoned that as well.

JXL, AVIF and HEIC use next-gen compressors and are about half the size of JPEG and WebP at the same quality. HEIC has a range of terrible patent problems, so the current choice is AVIF vs JXL.

AVIF has wider industry support and is likely to get hardware decode. JXL is technically more interesting and more flexible, and far better CPU encode/decode performance.