Yay! It's so awesome to see pics from your game.
(I am going to send you the other simmies sometime this weekend, I have to get on my game computer)
I also color the walls light - but sometimes I use a backdrop too. It's nice if you want a easy way to get rid of lines in the background.
This one, on TSR, has automatic lighting that works like the invisible lights (It's free, so no need to hunt it down on the booty):
This one, by Awesims, gives a night, soft, "ambient" sort of glow - but you have to use game lights with it. When it's recolored, you can get cool gradient effects. It's "Sixtyten’s photo backdrop":