The "selfie" has become part of the pop culture lexicon, and for celebrities mastering the art of social media, posting them is part of building their brands. Which is to say, a selfie is just another form of self promotion. So who's doing it best this week? We've scoured Instagram and Twitter to find the contenders for the best selfie in this week's Celebrity Selfie Showdown.Selena Gomez Miley Cyrus Beyonce January Jones Alessandra Ambrosio Jennifer Lopez Vanessa Hudgens Lily Aldridge Emmy Rossum Jessica Biel AnnaSophia Robb Bar Refaeli Bella Thorne Kelly Brook