TiltViewer is a free, customizable 3D Flash image viewing application you can add to your site to create a lovely, interactive wall of photos. In just a few minutes I put together a demonstration page to show off the effect.
The images are being pulled from my Flickr account, and if you click on the rotate icon in the bottom right hand corner, you can the Flickr description of the image along with some other data, which could make TiltViewer a nice little flash card exercise with the image on one side and answers on the reverse.
TiltViewer also integrates with Picasa or with a folder of stand alone images on your web server. And, best of all for us D2L users, I was able to get the application working in D2L without a lot of mucking, which is a bit of a surprise since anything that uses javascript often makes D2L very unhappy. Here is what TiltViewer looks like in D2L.
If you plan to use this with stand alone photos, it does require some mucking with an XML file, but the instructions are straightforward.