)) I'm not a coder so I can't give you any specific answer. But as a photographer, I use many photo editing app. So, from users' view, I think you should create an app that is easy to use (I mean, the instruction is clear so that even the new noob beginner can use it); diverse functions ( I stop using open camera and some other app because their functions are so poor, just rotating and cropping!). Seem that I've just give so general answer .____.