Recently I got my first IPhone (4s). I have been in love ever sense then. Not so much with the phone as with the apps! I have an IPad mini also. Between the 2 of the them I now have a fairly large collection of apps. I don't just have "free" apps but purchase some of the apps also. I have to admit some of my favorite apps are the photo editing ones.
This is one of my favorite photo apps. MOKU HANGA HD. Currently listed at $2.99.