Maybe you've tried too hard, Abigail. Some people just don't want a close relationship with ILs and that's that. I don't get it but some people are like that.
Even though you have photos of all family around the house, DIL may still think you have "too many" of GD. And, I can't know, of course, maybe it does look like "a shrine" to GD? But you know what? As PPs have said, that's you're right. DIL doesn't get to dictate what photos go up in your home, anymore than you could decide what ones go up in hers.
Still, you could put some in albums, as suggested earlier, if that would help. But thinking this over, I realize that might just make DIL feel she has some clout in YOUR home. On the other hand, if you feel she's really hurting under the "no kids" decision, it might be a kindness you'd be happy to do. Up to you, naturally.
Other options would be to see them only in their home (if they invite you) or arrange to meet in a neutral setting.
Then again, now that you've given us a little more history, this all may just be an excuse to stay away since she's not that into you, anyhow. If they choose to join everyone for Christmas, fine. If not, oh well, maybe better for all. Again, you can always see DS and DIL on an alternate day (if they are willing), perhaps meeting up at a restaurant (neutral setting, with no photos of GD, etc.).