Somebody Randi shared it with used the tag (or comment) feature, which then caused it to show up in the feed of Randi's friends-of-friends. Those people had no idea that the image wasn't public (because they don't directly know her), and simply assumed it came through a public feed.
Randi thought that one of her friends somehow shared the image, which wasn't the case at all. They were simply using a common Facebook feature. She clearly misunderstood what was happening. And she acknowledged her misunderstanding by deleting her twitter comments on the matter.
""@cschweitz not sure where you got this photo. I posted it on FB. You reposting it to Twitter is way uncool," Randi said in her tweet."
It was reposted to twitter. Randi shared a photo on Facebook. This person was able to see it because she was friends with Randi's sister (friend of friend). The user then took the photo from a semi-private space and shared it publicly on Twitter.
Somebody Randi shared it with used the tag (or comment) feature, which then caused it to show up in the feed of Randi's friends-of-friends. Those people had no idea that the image wasn't public (because they don't directly know her), and simply assumed it came through a public feed.
Randi thought that one of her friends somehow shared the image, which wasn't the case at all. They were simply using a common Facebook feature. She clearly misunderstood what was happening. And she acknowledged her misunderstanding by deleting her twitter comments on the matter.