.JXL File Extension

In the 2010s and early 2020s, a number of organizations responded to the proliferation of Internet-enabled smart devices and responsive web design by introducing new image file formats optimized for web-based display and delivery. For example, the Alliance for Open Media introduced the .AVIF file format, and JPEG introduced the JXL file format.

JXL images are saved using JPEG XL compression, which is an iteration of JPEG compression. According to JPEG's website, JPEG XL "is particularly optimized for responsive web environments, so that content renders well on a wide range of devices." JPEG XL compression allows users to save higher-quality images in smaller-sized files than those produced using JPEG compression. The JPEG XL standard also supports animation, alpha channels, layers, thumbnails, and lossless coding. Most importantly, in contrast to AVIF, .WEBP, and .HEIF images, JXL images can be decoded using progressive decoding, which allows web browsers to show low-quality preview images to users before fully decoding a JXL file.