@graverobber: Program or no program, there is no way you could make this in 15 minutes. At the [I]very[/I] least I would say an hour - but I wonder at how good it could possibly be with a program making it.
See, maybe the program can put the pics together, but can it blend the edges and have a layer at the bottom for coloring to aid in blending? Can it place the pictures in their optimal spots? Can it make sure no two pictures of the same anime touch? Better yet, what about getting the pictures themselves? A program can't do that, either.