The picture of Eva is a mystery for many reasons. It's a picture she kept on a table of her in her late-twenties along with a man she had a brief relationship with. When Kevin is a child, the picture disappears, and Eva imagines Kevin took it to destroy it. But he didn't. The picture resurfaces after Eva has forgotten it—taped over Kevin's bed in prison. Eva sees it in the documentary, strategically placed for the camera.
This raises so many questions. 1) Why would Eva and Franklin keep a picture of Eva with another man on display? 2) Why did Kevin take it? Did he know that ten years later he'd be in prison and want it? And 3) Why does Kevin tape it to his wall? Does he actually miss Eva? Or is this a ploy for the documentary saying, Look, I miss my mother. And if it is a ploy, who is Kevin trying to manipulate: the public, Eva, or everyone?
We wouldn't be surprised if Eva were licking a Tootsie Roll pop in the picture: like trying to figure out how many licks it takes to get to the center, the world may never know what is going on with this little photograph.