I LOVE this, and I knew that I could use one of the old windows stored in my attic to create a similar look. I decided to make one for Kelli, because I thought it would be a great way to include photos from our trip to Africa.
I started by painting both sides of the window white. I had a piece of thin plywood from Home Depot cut to the same dimensions as the window (using the same piece as I originally used for Jacob's chalkboard to save some money), and covered it with paintable beadboard wallpaper (like this). I painted the wallpaper with a coat of light blue (it looks darker in the photos than in person), and kept the paint pretty light, so the grooves of the wallpaper would be more pronounced.
Because one side of the window was thicker than the other three sides, I needed to beef up the beadboard/plywood a bit on those sides so everything would lay flat. Luckily, I found a piece of trim that was the perfect dimension. I cut it down, painted it white, and attached it to three sides using my nail gun.
Finally I attached hinges to one side, then glued clothespins (painted white) to the beadboard/plywood in just the right places so the photos would be centered in the window panes.
When the window is open, it looks a little rough, but you can't tell when everything is closed.
Once I put the photos in, I found that some of them tended to fall out of the clothespins, so I added some pieces of foam to the backs of the photos to beef them up a bit.