iPhoto for iOS doesn't contain ANY pictures. It displays pictures from the Camera Roll. All of this information is backed up in your iOS backup, either to iCloud or to your Mac/PC using iTunes.
I've never had to try and retrieve just a single item from an iOS backup, so I'm not sure how that would work, sorry.
However, my Photo Stream (ie, all the photos I have taken on the iPhone) and my camera roll automatically back up to iPhoto on my Mac. So in my case, if I needed to retrieve an image accidentally deleted from the iPhone, I would simply restore it from iPhoto through iTunes.