Snapseed is an excellent app for post-editing photos and images. It is easy to use and has an extensive range of editing tools and filters for post-processing.
One of the great aspects of Snapseed for editing images is that you can post-process images. That means that your original image remains in your camera roll without being affected by the editing process. Therefore you keep your original along with one or more edited versions of the same photograph.
Download Snapseed from the App Store