Dave - I've used hollow core door anchors. These are short, self-contained anchors with a pointy tip. You don't need to make a really big hole and they tighten up pretty good. Sometimes you will have to hold the anchor with a pair of needle nose pliers until it grips the panel. I've also use the spring type anchors that Nash mentioned. Only problem with then is you have to drill a bigger hole. And with my luck, the drill bit will sever some electrical wiring in the wall. For hanging pictures, I prefer industrial strength double sided tape - the same that is used to hold molding on cars. You can get it at the auto parts store. Be sure and put a piece on all four corners.