i can see both sides of this - i understand the mothers need, and she obviously feels comforted by this pic, but i can understand having a pic of dead baby on show, in your face all day could be upsetting to some - especially if they too have suffered miscarriages or still births, and especially if the baby does not look like it is just sleeping.
the mother must also have consideration for others affected. they have a right not to be forcibly reminded every single day of their own loss.
she does not HAVE to have the picture there, it will not affect anyone if its not there.
perhaps in a few months she will not want to be reminded all day everyday - there is no way she can even begin to move on somewhat if that is there all day.
you would not put a photo of someone in a coffin on your desk, no matter how much you love them.
there is a need for sensitivity and compromise on both sides here - if its her own desk she should keep it in a place out of plain site, perhaps only visible if you are sitting it the seat or somewhere such as in the drawer or on the inner side of her computer or something