This is the primary issue, without even going into the obvious power dynamic between child and parent when it comes to consent later. Where do a childs rights end and parents begin?
Again, if we argue that children have to consent to get their photo taken, no one should take any photos of their children below the age where they can do that. That means no baby pictures at all.
The “real psychological pain” part makes it look like you’re dismissing trauma
You have no evidence of this trauma. You're just guessing.