JPEG XL image coding system is particularly optimised for
responsive web environments so that content renders well on
a wide range of devices.Existing JPEG files can be losslessly
transcoded to JPEG XL and can also restored to exact same JPEG
file ensuring backward compatibility.

JPEG XL is designed to meet the needs of image delivery on the 
web and professional photography. It supports wide colour gamut 
as well as high dynamic range and high bit depth images. JPEG XL 
further includes features such as animation, alpha channels, layers, 
thumbnails, lossless and progressive coding to support a wide range 
of use cases including but not limited to photo galleries, e-commerce, 
social media, user interfaces and cloud storage. To enable novel 
applications, it also adds support for 360 degree images, 
image bursts, large panoramas/mosaics, and printing.

Optional dependencies:

Sphinx and sphinx-rtd-theme is needed for building the html
documentation.

qt6 is needed if you want comparison tool,flicker test tool
and directory viewer.