Oh, that explains! I tried AVIF and JXL a few years ago and one of the two took ages to encode (a minute versus <1s for jpeg) to get similar compression ratios, and the other was somewhat reasonable on cpu complexity but significantly worse quality at the same size / much bigger to achieve the same quality as good old jpeg. I ended up concluding that jpeg is still the best for the specific image I was trying to lossily compress, but that was probably just the encoder then