In "The Pick," Jimmy could never understand how Elaine's nipple could barely be visible in her Christmas card photo. Either it's exposed, or it's not, right? But Jimmy never considered a nipple slightly showing through a "sheer blouse"... until Jimmy came across this photo. You have to look close, but you can see a nip showing through. Could this have been the inspiration for the barely visible Christmas card nip?
http://www.hissandpop.com/celebrities/d/julialouisdreyfus/photos/017.jpg