If you need something a bit more robust than your average Instagram editing tool, you're going to want to look into Pixelmator's new app for the iPhone. Whether you need to make a simple color tweak or get your hands dirty with a multi-layer edit, the app brings all that desktop-grade image editing capability to the palm of your hand.
You also get extensive Photoshop file support so if you need to work on a file, Pixelmator is able to hand many of its most popular features. If you use Pixelmator on your iPad or Mac, they've also enabled the new Handoff feature so you can continue your work on any of your favorite Apple devices.
$4.99, available now at at the App Store