Some suggestions

[esator]

I saw that gcc compiler for some compressors can drop performance significantly (especially for encoders by jxl devs, from 20% to several times on my hardware on some images, I was comparing gcc 12/13 and clang 15), it would be good to see a comparison with clang

Also about some additional good compression to speed modes from the benchmarks formats:

• WebP_Lossless with z0 (fastest) preset
• JXL_Lossless/l2 (effort 2 for libjxl) fast and good for mixed images
• JXL_Lossless/f1 (effort 1 for fjxl)

What about Zstd for QOIR or any of the other relevant compressors?
As an example:
https://github.com/inikep/lzbench/blob/master/lzbench18_sorted.md

What about multi-threaded comparison?
Like for 8-threads (enough to show scalability), because not all formats/implementations scale equally or may lose efficiency compared to single-threaded

And another QOI-like experimental format mostly for photos and not supporting alpha yet (from what I understand):
https://github.com/MarcioPais/SIF
https://encode.su/threads/3917-SIF-Simple-Image-Format

[dumblob]

@MarcioPais might of interest to you 😉