Detect when the user takes a picture or when a new image is added to the camera roll

Question

In my application, I have an image view showing the most recent image from Camera Roll.

I want it to always be updated, so I need a way to detect when a new image was added to Camera Roll.

Is there a notification when a user takes a picture from a camera or a screenshot? Or better yet, is there a notification that a new image has been added to Camera Roll?