wallpaper-to-lightdm

#!/bin/sh
Wallpaper="/home/matt/.cache/wallpaper/*" #must be pointing to your home directory instead of 'matt'
LoginImage="/usr/share/backgrounds/warty-final-ubuntu-unchanged.png"

if diff $Wallpaper $LoginImage >/dev/null ; then
    echo "The LightDM background already matches your current wallpaper."
else
    echo "The LightDM background does not match your current wallpaper. Let's change it."
    rm -rf /usr/share/backgrounds/warty-final-ubuntu.png
    cp $Wallpaper /usr/share/backgrounds/warty-final-ubuntu.png
    cp $Wallpaper /usr/share/backgrounds/warty-final-ubuntu-unchanged.png

    #darkens, desaturates, and blurs the image. comment this out if you want
    #requires imagemagick to work -- sudo apt-get install imagemagick
    convert -modulate 40,40 -blur 0x10 /usr/share/backgrounds/warty-final-ubuntu.png /usr/share/backgrounds/warty-final-ubuntu.png

    echo "Done."
fi