Hi Wilfred,
Thank you for your reply. OK, I've gone People, found the contact that I want to add the photo to, and then clicked and double clicked the icon of the person (it's in gray, as your image shows). I even started by click on the "Edit..." link to the right (in Outlook 2013), but no matter what I can do nothing with that icon. Does that mean that my contacts are in the Group Address List? Is the Group Address List something that's maintained by my employer?