Huh, Photoshop has its own class. But it's just overkill if we want basic featured. If your phone is based on Android Platform, there is no lack of Photo Editing Apps. Some of which I have personally used are PIP camera (Which will enable you to put Picture within Picture), AfterFocus and Picsay. All apps have different functions and features. For reference you can visit Best Android Photo Editing Apps.
Or you can go to Google Play Store and Search the apps.