Support for webp?

[xenogenesi]

Thanks for sharing this project, I'm thinking of adding support for webp, from the closed issues it seems to me that stb has no intention of supporting it, see Will you add more image types to stb_image.h?
This project interests me mainly to evaluate if and how to convert a quantity of images into webp. Before trying to add support I wanted to ask if you already plan to support it

[romigrou]

TL; DR: no plan nor desire to support WebP or any other file format not currently supported.

Thanks for your interest. Support of any file type is beyond the scope of this project whose main purpose is to provide a library to compute SSIM. It so happens that I needed to be able to load images for the unit tests and this is why I used stb_image. I also wrote a sample, still using stb_image. Writing ssim-cli was not much more work and proved convenient to some people, but it is really not an end in itself.