Distortion metrics can be found here.
Large images were first encoded with Mozjpeg at q85 filesizes. Big is 125% of Large. Medium is 60% of Large. Small is 60% of Medium. Tiny is 60% of Small. Everything else was matched to +/- 5% filesize.
All the pictures have been compressed from RGB PNGs.
This study compares 6 differents encoders:
The Python scripts used to generate the compressed images are available on the GIT repository. The configuration file containing the codec settings is recipes.json.
This page is based on eclipseo.github.io comparison page. Originally developed by xooyoozoo. A list of sources for the images can be found in this text file.