CPNG is a fork of the PNG image format, designed to bring it into the modern era. The creator has been working on adding new features to PNG that are backwards compatible with all browsers, operating systems, and engines. These features include faster encoding and decoding, SIMD encoding, multithreading, and support for HDR pixels. The CPNG format is still compatible with existing PNG files and decoders, but offers improved performance and additional features. Some of the features, such as constrained deflate and FP16 support, have already been implemented in other libraries. The goal is to create a format that is viewable by all browsers and systems, even if they don’t support HDR.
http://richg42.blogspot.com/2023/12/announcing-cpng-compatible-network.html