Why did his ex add me on Facebook?

The guy I like/ is a good friend of mine has an ex that really tore him up emotionally and she added me on Facebook. I asked her if Ive actually ever met her and she said- "No, (blank) is just my really good friend and I saw a couple pictures of you and him." she didn't add anyone else in those pictures?... Am I just over thinking this? Or does this mean something??