Crush the pngs

png-crush.sh

#!/bin/sh

# Cause stefano said: You can get them even smaller with
# http://www.advancemame.it/comp-readme.html after crushing
# it operates on the deflate compression, not the PNG image data

git ls-files | grep \.png$ | while read img
do
    echo -n "$img..."
    size_old=$(stat -f%z "$img")
    advpng -q --shrink-insane --recompress "$img"
    size_new=$(stat -f%z "$img")
    echo $(expr $size_old - $size_new)
    if [ $size_old -le $size_new ]
    then
        git checkout head "$img"
    fi
done