I made this for my best friend's birthday. It took a lot of trials before I finally got it right.
Here it is all lit up, I used a piece of blank vellum on top so you can't see the innards. The bottom is open.
Here it is un-lit
Here are the lights
Here's the corner bracket I used, put one in each corner, at the top and bottom of the corners.
I finally used 4 picture frames of the same size, some corner brackets, and I printed the pictures out on vellum on my home ink jet printer.
For the pictures I used photoshop to crop pics of my friend's kids and put them on different backgrounds and to make them black and white. I attached the pictures with sticky dots to the frame, and then I put another piece of vellum behind the picture so it wouldn't be too see through.
The lights were little battery powered LED rice lights that I got at Hobby Lobby. I used two 20-packs. I found them after the stock boy I asked told me that they didn't carry battery powered LED lights. Just goes to show how much their own employees know (I found them in the Christmas aisle). The pic makes them look blue but they're really more white than blue. I put them in a little vase just so they would be easy to maneuver. If I make another one of these I think I'd staple the lights along the inside of the frames.
The main snag I ran into was attaching the corner brackets. I finally found some really short screws instead of using the longer ones that came with the brackets. I used black electrical tape to cover the brackets and to also keep them from sliding around since the screws didn't fit very well in the holes.
All in all this probably cost me about $20-25, which isn't back considering I saw something like this online for about $150!