Replace apple ID photo with initials on iPhone

I recently bought my wife an iPhone 6s. I set up an apple ID for her for the first time and on the phone it somehow linked to a photo of our daughter, i.e. when I go into Settings / iCloud the photo shown was not selected by me. When I tap the account and try to edit the photo it only allows me to take a photo or choose a photo. We do not want a photo, we simply want initials (which is what I have on my phone and our daughter has on her iPad). There does not seem to be any way of doing this. In contacts on my wife's phone the details do not have a photo, but just initials. Can anyone assist? Many thanks.