Megosztott hang

There's a person in my photos who I've never met. I noticed it when I was scrolling through old pictures. In almost every photo from the past five years, there's a blurry figure in the background. Sometimes it's just a shadow. Sometimes it's a face I don't recognize. Sometimes it's a full body. But it's always the same person. And I have no idea who they are. I showed my photos to my friends. They didn't see anyone unusual. But I could see them clearly. In family photos. In vacation p