Desktop backgrounds

I know this isn't a Returnil specific question, and it's very low priority, but I figured I'd throw the question out in case anyone has a solution. I've put Returnil on a few family members PCs and got them up and running, moved their personal files to a separate partition so they are retained - everythings great however the one complaint I've received so far is the fact that changes to the desktop background are not saved. Does anyone know where these settings are stored? I'm guessing it's in the registry and not in the C:\Users\ where some of the other typical settings are saved?

Thanks for the help!