Photoshop Mobile. Yep, this is the mobile version of the best and most popular image editing application you can find for desktop computers, and it’s free to boot. It comes for the iPhone and Android devices, which just adds to its coolness. It is no where near as advanced as the full version, of course, but it is good enough for doing a quick edit on any of your pictures, so you can post them on Facebook or email/message them to someone. Its abilities include cropping, resizing, modifying and applying various effects (B&W, Sepia, Mosaic, etc.) to any of the photos available or taken with the phone’s camera. Download here