*shrugs* I dunno, I'd post a picture like that. I know that privacy settings don't mean much...and I doubt I'd go plastering it all over public forums or a blog or something...but sharing on a private FB or private photo-sharing site? It's a cute picture of a family sharing a bathing. ANY family photos can be creepy if the parents are abusing the child, and ANY photo of a child can be used in horrific ways. This photo doesn't show an excessive amount of the child's body, any more than a picture of her playing in a diaper, or in a swimsuit on the beach would.
Years ago, family photos were kept in photo albums or boxes or frames in the family's home. The only people who saw them were people invited into the home, or people you physically showed the photos to. Now, they're on the internet for all your family, friends, and often acquaintances and strangers to see, if you put them there (and even if you don't). I don't see anything wrong with this photo compared to other family/childhood photos going on FB, aside the idea someone might freak out about it.
Lots of chazzers post pictures of their kids, we've seen some tasteful bathtime photos on here. The only reason they haven't had a whole commentary is because the parents aren't in them. I'm sure if you go on Finnish or Scandinavian or Japanese forums where people post their kids, there are plenty of photos like that.