> FLIF is a novel lossless image format which outperforms PNG, lossless WebP, lossless BPG, lossless JPEG2000, and lossless JPEG XR in terms of compression ratio.
PNG was not designed to be used for photograph-like images. The rest of those were not designed to be lossless formats, the lossless version is just a tacked-on afterthought.
Very unsurprising to find a codec that can beat those.
In my own tests, I found FLIF generally beats PNG (PNG Crush/Optipng both in brute-force mode) for comics (greyscale, majority white) as well, but by a less significant margin.
It's also worth noting that there aren't many other lossless formats, so it's still a valid comparison. I'm sure neither TIFF nor RAW outperform FLIF either.
That's not a valid comparison for TIFF. TIFF is a container which supports multiple compression algorithms. You could plug FLIF in as a compression algorithm and use it directly.
It also loads progressively and has a novel feature that lets a client determine how much detail to render, then stop loading any more data, all while using the same file.
This would be a totally awesome feature if the quality of a truncated FLIF came anywhere close to files tailored to that size in “real“ lossy formats. Unfortunately, according to that example page, truncated FLIF falls far behind. It might find a niche where data reduction and scale reduction fall together (the last example)
> 74% smaller than lossless JPEG XR compression.
> Works on any kind of image