PIK is a raster image file format developed by Google. As of 2019-10, it is a work in progress. The project's source code was made public in 2017-07.
It supports lossy and lossless compression. Among its design goals are to work well with photographic images, and with the internet.
JPEG XL is reportedly based in part on PIK. It's unclear whether development of PIK has been discontinued in favor of JPEG XL.
PIK files begin with signature bytes
d7 4c 4d 0a.