This is kind of neat, but when I think of "HEVC-based image codec" I think of Apple's .heic format. Unfortunately I didn't see a high-level comparison to HEIC on Bellard's site, so I'm not sure what the advantages of BPG are. Wouldn't I want to use the more common format?
BPG came before HEIF. It was a great proof of concept, but there’s little reason for it to exist now. BPG was an impressive one-man spec; HEIF is based on input from OS developers, camera makers, IC designers, display manufacturers, etc.
HEIF is just a generic image container format. It’s almost identical in structure to a .mp4/.mov/.av1 file (follows ISO BMFF) and can be parsed in an identical way using a simple tree structure. That’s a perfect fit for wrapping a single video I-frame as an image, the basis of all of these new image codecs.
Note that video I-frames can often only be properly rendered using metadata from outside the bitstream, such as HDR characteristics, color profile, or orientation. Sharing that metadata structure with the codec’s canonical video format is the only way to be forward-compatible.
A HEIF that wraps AV1 frame(s) is an .avif
A HEIF that wraps HEVC frame(s) is a .heic
Codecs will change, but the HEIF container is probably the last bitmap file format that we’re going to need for decades.
