Unfortunately for the comparison-focused blog post the comparison widgets is pretty bad - you can't quickly compare 2 reference pictures (original vs AVIF or original vs JXL) at different scalings like here https://web.archive.org/web/20200915201019/https://afontenot...

(also like the BPP size metric that is picture size-independent)

Wish that widget with improvements (that allows comparison of 3 pics with 3 buttons: original/codec1/codec2) were the widespread standard (also, "hold" is a rather unergonomic action)

Otherwise, seems like AVIF has had impressive gains in both speed and quality, wonder whether JXL could catch up