Putting patterns into PS is easy once you get used to it.
1. Run Ps.
2. Open the picture you want to use as a pattern.
3. Click Edit - Define Pattern.
4. Done.

I'm not sure how Gimp works but I would assume it to be just as easy. I also think that you can add to the collection of patterns for DJ so putting more patterns in that would seem like the way to go so that way you can do 2,3,4 from your list. I have no idea what CC3 can do but I'm sure those who know will stop by and tell ya.