Hacker News Reader

Indeed! For one of the my images, which had lots of non-linear gradients and shadows (an app icon), an optimized (with the best algorithm using ImageOptim) 457 KB PNG got compressed to 36 KB WebP (lossless, of course).

Just for fun you can compare WebP vs PNG performance (in OxiPNG or your browser's implementation) on https://squoosh.app/. For your normal images this will quickly net your a 20-30% size decrease over optimized PNG even in lossless mode.

JPEG XL is even better, but browsers and other image libraries tend not to support it.

Unfortunately WebP only supports 8-bit images.

One of the main reasons I use PNG is that it can handle 16-bit images, so if I converted my archival 16-bit PNGs to WebP I'd lose data.

WebP isn't perfect but it's fantastic for raster web graphics requiring transparency!