Tbvh as long as you are not submitting a bowl of rice, or a photo of additional essays u wish them to read, then it will be fine. It can literally be anything, from a picture captured in the middle of a movie, to a self portrait, or even photo of your desk, as long as they can identify what it is then it will be fine. Please be reminded that it should be something meaningful to you.
I submitted a photo of a prop from a theatrical performance I took part in. One of my friend submitted a screen capture from a Wes Anderson movie.