Image Composites

I have 1615 images that need to be made into composites. There will be 538 composites total. I already have the template to put it in. 3 images go into each template and then the image is flattened and saved at 8 compression JPG. Need to be able to get files from yousendit and upload back. Each composite takes less then a minute. Needs this done ASAP. Attached is a sample of final file. Needs to be done in photoshop. Does not require any retouching. Just crop from one and place in template, flatten and save.