When looking at the benchmark result and image size, it seems like this format is good at images that have horizontal structures or where the same color is repe

When looking at the benchmark result and image size, it seems like this format is good at images that have horizontal structures or where the same color is repeated often. It's not good at vertical structures, including images with enlarged pixels (where one row is identical to the one above). I think the main reason for that is that PNG has a filter pass that can look at the row of pixels above, while this format only looks to the left. Example of image with vertical gradients: https://qoiformat.org/benchmark/images/icon_512/apps-preferences-desktop-locale.png https://qoiformat.org/benchmark/images/icon_512/apps-prefere... - qoi compresses to 186kb and libpng to 25kb Example of image with horizontal structure and repeated colors: https://qoiformat.org/benchmark/images/textures_pk/mod_walldetail1.png https://qoiformat.org/benchmark/images/textures_pk/mod_walld... - qoi compresses to 21kb and libpng to 33kb