Progressive decoding: JPEG vs JPEG XL vs FLIF
Example of what loading a big image over a slow connection would look like.
Download speed here is 30 kB/s, more or less what you get on 2.75G (EDGE).
This is a 5 megapixel image, encoded to roughly the same perceptual quality using 3 different codecs:
mozjpeg 4.0.1 (default progressive mode)
JPEG XL 0.1
FLIF 0.3
JPEG XL can either start showing something as early as possible (LQIP decode mode) or only show something when at least an 1:8 resolution is available; both decoding options are shown here. The .jxl file is the same one.
See also • Progressive decoding: JPEG vs JPEG XL vs AVIF for a comparison to AVIF and sequential JPEG.