Yeah. I agree with Aphrodite. It's not about the quality of the images, but how much you cut them into chunks and not overloading the system ram.
If you abide by those guides. CC and C2 shuold be fine. If you break those guides. There isn't a game engine in the world that will cope. it's all about the tricks :)
So if you want some suggestions. How about showing some of the image assets your using. Specifically the bigger and biggest ones. An average object count, how many objects on screen and how much many objects are trying to collide with each other.