Currently Being ModeratedApr 30, 2012 3:46 PM (in response to Han98)
iPhoto for iOS is not quite like the desktop version. It does not have the ability to directly send photos to an external editor but the photos it shows are simply your camera-roll photos. Any photo editor app should have access to your camera roll and all your photos. When you save out an edited photo you'll simply get a new photo added to your camera-roll it will not repalce the original. As long as the editor app you are using saves out to the camera-roll iPhoto will be able to read those newly edited photos.