Of course, the problem with these very specific types of thing, and please tell me if I'm wrong, is that they only occur in Catholic or Christian cultures. Which leads one to believe that the phenomena are culturally orented by human perception in one manner or another, and not in any fashion of a supernatural origin. All, one assumes, a relic (no pun intended) of the original image of the Shroud of Turin and the weight it carries in the Christian mind.