Camera.app/photos.app Bug
Using an iPhone with a passcode open the lockscreen camera and take a photo. Then view the photo and it should be labelled photo 1 out of 1. If you then delete the photo and press the "done" button the most recent photo taken with the camera is visible in the bottom left. When you try and view the photo, the screen saying "Unlock your iPhone to see all your photos and videos" appears.
iPhone 4S
Using an iPhone with a passcode open the lockscreen camera and take a photo. Then view the photo and it should be labelled photo 1 out of 1. If you then delete the photo and press the "done" button the most recent photo taken with the camera is visible in the bottom left. When you try and view the photo, the screen saying "Unlock your iPhone to see all your photos and videos" appears.
iPhone 4S