iColorama is a photo colorizing app on steroids. It has a vast array of features, from basic editing like saturation, cropping and editing, to all kinds of color and distortion effects.
The app comes in two versions, one for iPad (US$2.99) and one for iPhone ($1.99). I did most of my exploring on the iPhone version.
Although there are tutorials available, the app is straightforward. Load or take a photo, then get to work. Options scroll across the top of the screen, and when you select a process you will see more options and presets at the lower right. If you don't like the presets, there are all sorts of manual settings.
Photo editing can be subtle or pushed to the limit. Every user will find something that they like. You can make infinite changes and tapping on a new effect will wipe the old one until you hit the 'apply' button. Then you can send your creation out via the usual social networks, email, or save it to the camera roll.
I've seen a lot of filtering and editing tools, but I have to say iColorama has some of the most varied and powerful effects I've encountered in an app. These effects aren't for every photo, and it is easy to go overboard, but what is overboard for one person is subtle for another.
iColorama operated smoothy with no glitches. It's a handy tool to have in your photo editing folder. The apps require iOS 5.1 or greater.The iPhone version is optimized for the iPhone 5.