[greenavocado]

> for researchers to focus on lower-quality compression specifically

JPEG-XL already does this because it uses VarDCT (Variable-size Discrete Cosine Transform) aka adaptive block sizes (2×2 up to 256×256). Large smooth areas use huge blocks and fine detail uses small blocks to preserve detail. JXL spends bits where your eyes care most instead of evenly across the image. It also has many techniques it uses to really focus on keeping edges sharp.

[fleabitdev]

JPEG XL achieves about half the bitrate of an equal-quality JPEG, even at lower quality levels. That's a real achievement, but the complexity cost is high; I'd estimate that JPEG XL decoders are at least ten times more complex than JPEG decoders. Modern lossy image codecs are "JPEG, with three decades of patch notes" :-)

I think we're badly in need of an entirely new image compression technique; the block-based DCT has serious flaws, such as its high coding cost for edges and its tendency to create block artefacts. The modern hardware landscape is quite different from 1992, so it's plausible that the original researchers might have missed something important, all those years ago.