Thinking on why an abused girl might keep a photo? Perhaps because it was the only evidence she had to show in a world she knew was almost entirely stacked against her. In that instance I might keep the photo thinking that one day, when I was in a stronger position, I might use the damned thing to make the people who had wronged me pay - perhaps not in money, but with their reputation.
There are a couple of suggestions on here that coming forward and telling one's story of being abused might be distasteful, something that the poster wouldn't personally feel they would do...telling 'what was done to me' would be abhorrent to them. God, can you imagine how hard that must be....but the shame is not the victim's, is it?