Originally Posted by CielDuMatin
And personal comfort issues are VERY different from the issue of "outing" folks as poly. if you are concerned of being outed, then she absolutely needs to respect that.
I agree with this.
I also agree that you should probably talk to her instead of just having your boyfriend do it. If he accidentally (or purposefully - in my experience men like to feel validated and will often share their supporters' identities) says to her, "Well, papoly and I have been talking and..." to get her to stop posting, she may very well feel like you're doing it to attack her (kind of like you at one point perceived her posts as attacks to you). Direct communication so she can hear WHY you're worried about the posts would probably be better than second hand information.
On a side note, he can untag himself in the photos. I know that doesn't get rid of them, but then only her friends can see them (assuming she has good privacy settings on there) instead of his friends, your friends, etc. It may help a bit to keep the relationship under wraps.