Snapseed has long been a favorite image editing app among photo enthusiasts for the iPhone. It might have been the best $4.99 I've spent at the App store. Now the app is free, even better, and available for both Android & iOS.
Instagram is easy, but often I find the results disappointing. Nearly every image I share via Instagram or otherwise goes through Snapseed for tweaking - be it major or minor.
There a several enhancements in the scrolling tool bar including a crop tool, color adjustments, focus effects, and much more. Once you select a tool, menus are accessed by swiping up and down over the image. Adjustments are made by swiping left and right.
Photos can be saved to your image library or shared via email, Facebook, twitter and Google+.