See a new wallpaper after every suspend

My ubuntu 14.04 is getting crusty and I don’t think that Mate helped it out greatly, but I marginally like Mate better than XFCE. However, whenever my computer wakes from suspend, my wallpaper background image is all black and kinda messed up. So I read this example of making a suspend-resume hook. And here is my own:

jreynolds@cholla /etc/pm/sleep.d 
 > cat 20-desktop 
case "$1" in

   pgrep mate-session \
      && Esetroot $wallpaper &

And it seems to work pretty well.