Not a direct experience, but oh well.
My family is originally from NYC. We moved out when I was a baby, but my dad still works there and occasionally checks out the old neighborhood. Anyway, before I was born, my family lived in a shitty apartment on the top floor of a small building. My dad, out to lunch one day and just taking a stroll, decided to take a picture of the old place. He shows me this picture and points out the window to the apartment where they lived, and there's kind of a weird reflection on it. It looked like a father and daughter just kind of standing and observing.
Specifically, it looked like my dad and older sister. Except, as if they were 20 years younger, like around the time when they were living there. The man in the reflection was very slim as he was, and the daughter was a toddler, as my sister would have been. I'm not saying the images were clear as day. It was almost kind of blurry outlines with very vague features. Ghost-like, I guess, but still bearing a very uncanny resemblance to my family.
My father and sister are both still alive, which somehow makes this experience even more creepy.