I think the dangers of social media for kids is bigger than just what pictures are shared. Having chats with my sister about it in relations to my nephews and nieces and whilst pictures is discussed its just one aspect.
In fact the biggest topics are centered around what they can access, parents not knowing their kids have Facebook, Instagram and tiktok accounts at an age they shouldn't have.
About those platforms being targeted through algorithms bombarding kids with unhealthy adverts making them think they need to look a certain way to be accepted.
My nephews like most kids watch YouTube content created by other kids, I watched one with them and in it these kids were eating loads of candy and guzzling down 2litre bottles of coke (obviously not really) but it appeared that they had. Even my nephew said thats bad to do that but this is what they are exposed to.
Now there is AI you could be the parent who never posts a single pic of your kid but guess what someone can take you picture you parent's pic and AI can generate a pretty realistic pic of what your kid is like. Infact someone posted an AI generated image of what one of theirs face would look like on another thread some time ago...I hope it got taken down.
Then there's the danger of social media and not having the right settings applied if you do decide they are old enough to have an account.
Same with gaming how many kids are allowed to play violent games when they arent even the right age.
All any parent can do is do is educate themselves and do their best, is that what most parents are doing..their best. End of the day you cannot and will not be able to keep them safe from everything