I'm looking for the easiest way take multiple images of varying sizes and spread them out across a single frame for a slideshow. I have a hundred or so photos in JPG format and I'd like to have 2 or 3 of them on each slide. I'd like to end up with 30-40 image files of these slides. Any help is appreciated. Thanks. 
Here's an image to help visualize what I'm trying to accomplish 
Here's an image to help visualize what I'm trying to accomplish 