From what I've been told, it's some kind of individualized watermark that can be used to identify which person has been leaking content to the web. Once the pictures are out there (assuming the leaker didn't alter them to defeat the watermark) bots combing the web will be able to locate the...
Her photographer needs to turn down the damn ISO settings and increase the light source. So much fuzzy chromatic noise going on. It's making the autofocus go crazy too.