avif lossless bug

[golemus]

There seems to be bug in avif - save as lossless feature.

I have source file png of 11.6MB Below is what its size become when saving as lossless avif in different programs:

- image magic 5.6MB (quality=100)
- gimp 6.1MB (lossless checkbox)
- krita 6.2MB (lossless checkbox)

- xnview MP 15MB !! (lossless checkbox)


I think it can be reproduced with any file.

I am not sure how large it is of an issue as not yet sure which will become more important lossless saving algorithm (jxl or avif).

[xnview]

i've tried with libavif tools, and i obtain almost same filesize