Personally, I use `oxipng` if I want lossless compression. However, most of the time I use `pngquant` instead, since it gives significant size reduction even at `99%` (I can't even distinguish between the original and reduced image).
pngquant --quality=99 --ext=.png --force file.pngThat said, the best solution today is probably to just use a newer image format like WebP or (soon) AVIF if you need to meaningfully reduce image sizes.
But browser support is still disabled by default and AFAIK is still missing support for animations for both Chrome and Firefox. This was/is a problem with webp where aninated support came later without any new mime type so you can't fall back to gif / apng if it is not supported using <picture> - hopefully this will be handled better with jxl.
In general, I don't find optimizing png beyond the default compression level worth it for typical personal use. But can see why they are useful if you're hosting things.
And, I was comparing `pngquant` to `oxipng` sizes (not the default png output I get after creating a poster). For example, 70KB with oxipng changes to 32KB with pngquant at 99% quality level. This depends on the image of course, but most of the time I do see significant savings.