No, you can't programmatically delete images from the users Pictures MediaLibary.
"There is no way to delete any content from the user's library. Once you've saved a picture, the user will always have that picture unless they personally go delete it."
(Source Delete image from MediaLibrary.SavePictures).
If you need the ability to delete stored images you could store them in isolated storage and then have an option to publish them to the Media Library.