Sounds like you were r/raisedbynarcissists? (specifically, a Nmom)

Your profile says you're 13. Pics of when you were a baby are "passable" depending on angles, details and intention, but the problematic pictures are not shared in a strictly family group, but in a group of 200+ followers. Those will be saved, shared and end up in the wrong hands and I let you imagine the rest, therefor, what your mom is doing here is sharing underage content.

Naturism content, as you mentionned, is a grey area. The context in those pictures should make it obvious you were participating in a naturist setting or some way to prove you were raised the naturist lifestyle. Otherwise...

You are not consenting pictures of yourself being shared, and what you wrote proves it already has damaging consequences. Make sure your mom knows she's on the borderline posting those, and non-compliance of removal upon your request, she's playing with fire, a legal one.