Commandline image diff utility

imgdiff

#!/bin/sh
# Function to diff an image using imagemagick, displaying the original images
# and the diff.
#
# Add this file to your PATH to make available and ensure that it has
# executable privileges.
#
# Example usage:
#    imgdiff <image1> <image2>
# http://askubuntu.com/questions/209517/does-diff-exist-for-images

compare -compose src $1 $2 tmp_difference.png
convert +append $1 $2 tmp_difference.png tmp_difference_comb.png
display tmp_difference_comb.png

shift && shift
case $* in
    --delete|-d)
        echo 'Cleaning up diff images.'
        rm -f tmp_difference.png tmp_difference_comb.png
        ;;
    *)  
        echo 'Unrecognised command: '$*
        ;;
esac