JPEG XL
A newer image format offering both lossy and lossless compression, high bit depth, and lossless recompression of existing JPEGs.
Measured in
MB
In depth
Its most distinctive feature is the ability to repack an existing JPEG about twenty per cent smaller and restore the original bit-for-bit, which makes migrating an archive risk-free. It also supports progressive decoding, wide gamut and up to 32 bits per channel. Adoption depends on browser and operating system support, which has been uneven.
Examples in practice
An archive of 100,000 JPEGs recompressed to JPEG XL saves a fifth of the storage with no quality change at all.