pngnq quantizes PNG images down only a few colors. This can cause noticable color transitions on very plain areas, but greatly decreases the file size of the image. pngnq can quantize images down to only 2 colors, dither the output to add pseudo color, can sample more pixels for a more accurate quantization, and supports transparency.
Website 🔗️: http://pngnq.sourceforge.net
apt 📦️: pngnq
Fosstodon is an English speaking Mastodon instance that is open to anyone who is interested in technology; particularly free & open source software.