When I say the work itself the first thoughts that come to mind is the medium used. I mention this only because it seems that the medium seems to makes difference in the Average person’s eyes. Take the average person on the street and show them
Danaë by Tiziano Vecelli and most people would call the nude “art”. Now take that same person, show them a technically perfect, well light photograph of a nude women laying on a bed similar in most aspects to Danae and they will call it pornography or at the very least they will tell you that the photograph is NOT “art”.