What’s the best lossless image format?

(2021)

I wonder how AVIF and JPEG XL would stack up today.

There's been discussion lately whether or not JPEG XL adoption will be hindered by patents.

https://patents.google.com/patent/US11234023B2/

https://www.theregister.com/2022/02/17/microsoft_ans_patent/

I think decompression times would be a relevant criteria, but they're surprisingly not there...

I would love to see an estimation of how small real world images would get if we could calculate their Kolmogorov complexity.

Aka if we could find the shortest program that produces the image as output.

Some images obviously would become very small. For example an image that is all blue, a spiral, the flag of the United States, the Mandelbrot set ...

But what about the average portrait for example?

> What is the best lossless image format?

For which application? Otherwise you can only say "depends". Tiff is good if you want to save data fast to disk in Blender. EXR is great if you want 32bit color depth, etc.