lockSafe cydia tweak allows you to discretely store images from your camera roll, and easily access them from the lock screen.
Easily add images from all your photo albums, and store them in LockSafe. A simple swipe down gesture on the lock screen opens the password entry window. After adding images to LockSafe you can then delete them from your photo library. You can also tap on your images to view them fullscreen.
Configure options from Settings.