Graduate Ghost Picture

This ghost picture is weird, in that it appears to be a grayed-out apparition behind the crowd. There is no explanation of how he could be in shadows, when there is nothing in the picture to cast a shadow on him (he is darker than the rest of the people). He has lost all color - is it a ghost or someone in the shadows? You's the story and picture from Chris:

"My wife and I were wondering if this was a ghost or not. I took this picture at her MBA graduation last year. Going though the photos, I found a guy...or what represents a guy that wanted to graduate, too. He is located under the sign that says 2005 - he is in a cap and gown, too."