How to make a Grand Theft Auto cover collage using an Iphone?

I want to make a "Grand Theft Auto" theme collage of pictures on my iphone and i can't find no possible way to do it. I don't have photoshop on my computer and i also can't even find a website that would allow me to make the GTA themed collage. Can anybody help me out?

Two choices:
1) Get GIMP on your computer. It's a lot like Photoshop, but free software.
2) Get Diptic on your iPhone or some other collage app. Make two collages of 5 pics each, then combine the 2 collages so you can have 10 in one collage total. Not sure how well that will work though.