Never mind the reasons why you want to hide some pictures, we're just telling you this jailbreak app makes it easier to do. SwapCamRoll is an app for iOS 4 that essentially gives you two camera rolls on your iPhone. Only one is active at a time while the inactive one hides on the "flip side", completely inaccessible on the phone until you activate SwapCamRoll. (You can navigate to either folder through SSH though).
So if you have some er, private pictures that you don't want others to see when they're scrolling through your photos, then you can create an entirely new camera roll that can be swapped out for the default. For some, it just might be the app you never knew you needed!
So how does it work? The app is pretty bare bones, but does have some options that may be confusing to new users. Read on for the breakdown: