It'd be awesome to port pngquant to JS, especially that JS is getting parallelization and SIMD now.

Unfortunately I never got emscripten to work on my machine. Could you give it a try and compile http://pngquant.org/lib?

sure i can give it a go. though i'm currently stuck in an airport going on 14h. i'll ping you when i get around to it but could be a few days