Its crazy right!? The internet is just isnt a place for children, its literally impossible to ring fence and set boundaries or age restricted content, and you have no idea what their photos could be used for/linked with.
So many people seem totally oblivious to this though. My DD is only 2 but we've made it clear to all family and friends that her face isn't to be posted to any social media and we're going to set some quite strict rules about Internet access and if a mobile phone is needed in her teen years it'll be a dumb phone with zero Internet access. I forsee so many issues though and I've found it incredibly rare that anyone takes this approach. He cousin is 5 and has unsupervised access to tiktok! Another friend has countless photos, videos, and details about DCs posted across all their public social media accounts, details of school, clubs, birthdays, everything. If anyone had nefarious inclinations they could easially find everything they need to know about that child in a few minutes.
And the effect on children of seeing all this content... I think we're only just starting to see the fall out from it but I expect the mental health of our youth is going to continue to decline staggeringly fast. The porn aspect is so incredibly concerning though, the chances these kids will go on to be abusive is high, at the very least they'll struggle to form a normal sexual relationship in adulthood as expectations won't match reality by any stretch.