A random visitor, seeing photos of a newborn, would probably politely ask: "How cute! How old is he now? What's his name?" etc. and the inevitable answer would make the visitor just feel like dirt, no matter how the answer was handled.
Don't feel like dirt if someone tells you of a child that died. It means a lot just for the acknowledgement of their little life. You feel crazy grieving a stillborn or miscarried baby because you haven't lived with them and other people have never seen them. Pictures help you know that all the love and pain you are experiencing are for a real reason, a real human being.
It isn't possible to know the pain of losing children, at any age. I know I was very surprised at the depth of my grief at the experience of two late miscarriages. It hurt as much, and in many ways, more then losing my father.