Compressing PNGs for delivery on the webEdit

Prerequisites

$ brew install pngcrush pngquant optipng

Usage example

Lossy compression using pngquant, followed by an additional pass with optipng:

$ pngquant --force --ext .png --speed 1 file.png
$ optipng -o7 file.png

Non-lossy compression with pngcrush:

$ pngcrush -ow -brute file.png

In an extremely scientific test that I did, I wound up with these sizes, which would tend to confirm the above recommendations (ie. pngquant + optipng when lossy compression is acceptable; otherwise pngcrush):