Ticket #1576: optimize-images

#!/bin/sh

for x in $(find images/ -name "*.png"); do
        echo "Processing ${x}"
        identify -quiet -verbose "${x}" | grep "alpha: 1-bit" > /dev/null
        if [ "$?" -ne "0" ]; then
                # non-1-bit-alpha image, process normally
                optipng -o7 -quiet "${x}"
        else
                # disable color type reduction because that will break
                # transparency for the images in JOSM using the current
                # image loading method (see #1576)
                optipng -nc -o7 -quiet "${x}"
        fi
done