Comment 6 for bug 385074

For many of these images, I think you want lossy compression. I played with quick-start-summary.png a bit and got the best results (on Linux) using gimp 78.5% savings. ImageMagick's color reduction seems rather broken to me. It produces very unexpected results, particularly for images with alpha transparency. "optipng -o7 quick-start-summary.png" gave a 24.7% savings.

I found the best looking results using Adobe ImageReady CS. Only 64% smaller, but the results definitely look better than the Linux quantization tools. The best overall result would probably be from using ImageReady to quantize the images and then optipng to compress them optimally.

Probably way more thought than is needed for this ;) But if they will be used, I can perform those steps on all the PNGs in the docs and upload them. Just let me know.