B.M.
I would encourage her to hire a professional for at least some of the photos before or after the ceremony so she has some portraits. I know people who actually are professional and have told me that weddings are really stressful because if you miss something, it's gone forever. He takes multiple cameras and other equipment to make sure if something stops working, he has a back up. I personally think that's a lot of pressure for you. You also won't get to enjoy the wedding. And, if she doesn't like the pictures, she can blame you.