Snapseed (free - no IAP) is a high quality standalone photo editing app for Android. Users can easily edit your photos using many of the built in features like auto correct and selective adjustments. Free from Google and included in the G+ app.
Pro High quality photo editing
Snapseed includes many features of high end photo editing software, auto correct, image tuning and other effects. Snapseed makes editing your photos easy and gives the photographer many options to choose from in how they present their images.
Scrolling up and down lets the user choose from different effects and tools, swiping left to right determines the intensity. This app includes many effects such as tilt shift that are hard to find elsewhere.