Adobe Photoshop Express
What it does: Crop, rotate, and enhance images by experimenting with several one-touch effects controls, or perform manual touch-ups by utilizing your smartphone's multi-touch functions. Play with three filters (Soft Focus, Sharpen and Sketch), undo/redo changes, and take photos directly from the app without switching to the phone's camera mode. Upload and store up to 2GB of photos and videos on Photoshop.com, or share everything among your social networks. The premier graphic design program is now yours in mobile form for free.