The Plugin Site Forum

Well, I am not sure what you mean by slides, (I am more of a novice than a pro) but I used my digital photos and there is an operation in Picasa whereas you click on whatever photos you want to combine, and with the click of another button, it collages them together to create a melded image.

Have you looked at Picasa, by any chance? They have a feature for making combined-image collages.