It's nice looking for sure but much more complex than using `wkhtmltox` with `pngquant`, `optipng` and/or ImageMagick `convert` locally - esp. since the learning curve seems to be about equivalent.

Won't you need to install extra libraries for these?

Yeah, I thought that as well. So I was wondering if that's some kind of a joke, or maybe modern html is so fucked up that all usual solutions became obsolete since the last time I did that.