YANBU. I had pictures of my DD on FB, locked down so only my friends/family could see them and I had repeatedly asked them not to share them, which noone did. I'm funny about who sees pictures of my DD due to the line of work I'm in, but we live overseas and my security settings were high, so I put a couple on so people could see how she was changing. All fine.
My MiL decided to tag one of her internet "friends" on my DD's pic so she could see it. I do not know this woman - more importantly neither does my MiL. This woman could be anyone. This woman could be a man. This woman could be a paedophile. Point is my MiL does not know her. Tagging means that my DD's pic goes on this woman's wall, and into her pictures so everyone she has on her FB can see it.
I then go and look at this woman's page and she has NO security settings! Nothing. Anyone on the bloody planet can see any of her pictures - including the one of my DD - who she doesn't know!
I was livid.
I deleted the tag, then I deleted every single photo of my DD from FB. I also messaged my MiL firmly telling her that I was angry, that she had done the one thing I had asked her not to and shared a pic, and she'd shared it with a stranger with NO security settings which meant anyone could access it, take it and do what they wanted with it. I told her the pics were gone.
She had an almighty strop at DH, told him that FB is the only way she sees DD growing up as we live away yada yada yada..... My response was tough biccies - the pictures were there, you did something I asked you not to do and did it in the worst possible way, the pictures are gone. Shit bust. She ignored me for a while, but she got over it (had to or she wouldn't have seen DD when I went over - can't arrange a visit if you aren't talking to someone!)
There are now no pictures of my DD on FB - and it's going to stay that way.