QOI - The “Quite OK Image” format for fast, lossless image compression
Single-file MIT licensed library for C/C++
See qoi.h for the documentation.
Compared to stb_image and stb_image_write QOI offers 20x-50x faster encoding, 3x-4x faster decoding and 20% better compression. It's also stupidly simple and fits in about 300 lines of C.