QUAIL, the Quite Useful Advanced Image Library, is a new image codec inspired by Dominic Szablewski's excellent QOI. On QOI's benchmark image corpus, it achieves average file sizes 10.0% larger than lossless PNGs generated by libpng, while being considerably faster. Unlike QOI's byte-oriented encoding, QUAIL uses a more complex (and a bit slower) nibble-oriented encoding. It also provided a fun project to start learning Rust. (The quality of the Rust reference source probably reflects that fact.)
Compared to QOI and my earlier QOI-Remix project, QUAIL produces moderately denser files at a moderate performance cost - though it remains far faster than libpng. The repository has detailed performance and density measurements from the qbench tool (derived from QOI's qoibench.) It also includes a spec and reference implementations in C and Rust.
I'd love to hear from you if you end up using QUAIL for anything. Email me at sunset@arcanesciences.com.