Overlay with Image from Album?

[DenVog]

Can anyone shed some light on how are people overlaying graphics on top of images from the Photo Library or Saved Photos Album? I see several apps that allow not just the overlay and combined image to save, but also the ability to move and resize.

The cameraOverlayView that appeared in OS v3.1 works great with

cameraPicker.sourceType = UIImagePickerControllerSourceTypeCamera;

but per the docs

You can access this property only when the source type of the image picker is set to UIImagePickerControllerSourceTypeCamera

So you can't use UIImagePickerControllerSourceTypePhotoLibrary or UIImagePickerControllerSourceTypePhotoLibrary or you end up with:

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Source type must be UIImagePickerControllerSourceTypeCamera'

Suggestions or examples greatly appreciated.