Wait, so lossless webp manages to be smaller than even lossy jpg, while also having to losslessly reproduce jpeg artifacts, which tends to otherwise greatly increase file sizes (as compared to the original lossless file) in lossless formats?

[–] GamingChairModel@lemmy.world 2 points 1 day ago

JPEG XL has a mode for losslessly encoding any lossy JPEG into a smaller file size without any loss of quality. Wikipedia has some description of general approaches for losslessly encoding JPEG files further.

I don't know if webp uses any of these tricks, but I don't see why it would be hard to imagine that compression artifacts from a 30-year-old format can be encoded more efficiently today.