while [ 1 ]; do
	num=`ls ~/Backgrounds/* | wc -l`
	rand=`jot -r 1 1 $num`
	i=0

	for f in ~/Backgrounds/*; do
		if [ $i = $rand ]; then
			gconftool-2 -s -t string /desktop/gnome/background/picture_filename $f
		fi
		i=$(( $i+1 ))
	done

	sleep 900
done