Leonardo - Photo Layer Editor

Universal Photo Editor with support for Layers, Selection, Masks and of course filters, effects and other tools.

(Note that on iPhone 4 the max supported resolution is 2048x2048)

An editor so powerful that you could do almost anything that you thought was possible only on a desktop.

√ True layer support, just like photo editing on desktop.
√ Selection. You can select an area and work with filters and effects only on that area.
√ Layers can be masked. And not just with brush, you get a whole set of mask editing tool.
√ Layers support all that a true layer app should. Blending, Opacity, Transform, Duplicate, Merge and flatten.
√ The app is so fast that most of the operations are real time. You dont have to wait while adjusting the sliders.
√ Handles Exif, IPTC, Geotag etc. You can even edit Geotag and IPTC.
√ Exports PSD with layers. And of course exports JPEG and PNG too.
√ Copy/Paste with selections and masks.
√ Undo/Redo.
√ Powerful filters you will hardly find on many other apps.
√ 25 preset photo effects.
√ Tools like Crop, Straighten, Clone stamp, color gradient, paint brush, red eye brush and add text etc.
√ You can save your projects with all layers and selections preserved and work on them back and forth.
√ 18 video tutorials.
√ Resolution up to 4096x4096 on iPad3 and above, 3264 for iPad2, iPad Mini and on iPhone max resolution is equal to the resolution of the built-in camera (Except for iPhone 4 where it is 2048x2048)

And yes, it runs on both iPhone and iPad.

Note that reduce noise filter is available only on iPhone 5 and iPad3 and above.

To get maximum resolution you will need to...
1. Go to home screen.
2. Press on the "?" button.
3. Under resolution, select the max.