[tracker1]

IIRC, you're limited to 256 colors total (including those with an alpha channel)... it works pretty well, but it really depends on the picture in question. I use pngquant all the time myself... :-)

[ashmud]

Color quantizer (http://x128.ho.ua/color-quantizer.html) lets you use up to 12-bit (4096 colors). For command line, the author has TruePNG (http://x128.ho.ua/pngutils.html).

[mark-r]

That's interesting, since there isn't a 12-bit PNG format. Do they leave it in 24 bit then, and just rely on better compression due to fewer unique bit combinations?

[ashmud]

It looks that way. Irfanview reports 24bpp for images saved when I selected > 256 colors in CQ.