A great mystery...
Whenever you see an image, photo, lobby poster, DVD cover, internet ad, etc of a movie, they always show pictures of the stars (Like Joe Jones on the left and Mary Smith on the right) but the billing, the way they print their names, is always reversed: ("starring MARY SMITH and JOE JONES"). This can be very confusing when they are the same gender and you don't know who they are.
There must be a reason for this, because I have yet to see a counter-example, but I'll be hanged if I can figure it out. Can someone help me out here? It's driving me nuts.