Here's a quick example of the GOTCHA app I talked about yesterday. It's a class library and test windows form app. It takes a background and as many images as you want. Then it randomly assigns numbers between an assigned Min and Max to each image, and rotates them. I also make sure that there is no image overlap (some could be good though). Finally it generates the question and the answer. The question is in the form "What do you get when you add the {0} and the {1}?"
Where 0 and 1 are the names assigned to the images. Here is a screen shot of the test app:

Let me know if you use this on your web page or blog!