Xmonad - Random Background at Interval

Make a file randombackgroundatinterval:

#!/bin/bash
while x=0;do find $1 | grep 'jpg\|png' | shuf | head -n 1 | xargs -i xloadimage -border black -onroot -fullscreen '{}'; sleep $2; done

run it with the top directory for images and how often you want them to change.

example:
./randombackgroundatinterval /home/<YOUR USER NAME>/Pictures 3

Would pick a random jpg or png from the /home/<YOUR USER NAME>/Pictures directory, and its subs and display a new one every three seconds.