Some are pre-loaded into the "game" in the pokemon's profiles, others are just found through experimenting with paint and applications like this: http://pokedex3ds.tumblr.com/post/61554428...ts-what-i-think
I found Reshiram after looking through the inverted versions of all the ones I've seen.
I found Reshiram after looking through the inverted versions of all the ones I've seen.