I was trying to learn swift and to find some swift examples to learn from. And currently(2016), as Swift is too young, many examples online are for objective-c. And most examples of swift are too difficult for beginners.
This one original from https://github.com/larryhou/swift is so far the best one I can find. But it is from swift 1. I do not know how to contribute to the original fork(maybe later I would merge mine to it. For now I would just build in my own account.
bug unfixed in photoviewcontroller.swift. line 127-143
Thanks to Sample Video.