The compression of Inkscape’s PNGs is alright. It’s not overly impressive, but it’s a good compromise. I think it’s (Deflate) level 9, which is pretty much the same thing as the “maximum” Zip compression setting in many archiving applications. That means you get rather good compression (unlike Photoshop’s export for example) for very little time.

PNGOUT, PNGcrush etc compress stuff over and over again to find a hopefully optimal (”very good” actually) solution. Doing that for a somewhat bigger image on a slower machine can easily take hours, which usually isn’t acceptable.

PNG isn’t all that great anyways. It’s just not as crap as GIF. Something like PNG with LZMA instead of Deflate would be a lot better. Given how long it took Microsoft to support PNG properly… it’s only a matter of another decade.

Also, creating another dependancy for inkscape is harly a new present to most package maintainers