The white silk gauntlet has been thrown down. It looks like R.S.V.P. -- Memphis monthly society magazine whose daring photojournalists regularly risk life and limb to bring back rare, nearly impossible-to-get shots of expensively clad party animals clutching their drink in one hand and their date in the other -- is facing stiff competition. Elite, a shimmering, full-color magazine featuring breathtaking, hitherto unimaginable photos of toothy cocktail-toting socialites prowling about in their natural habitat, made its auspicious debut this month. Critics of R.S.V. P. who claim that the publication s obviously biased shutterbugs only photographed Kevin Kane from one decidedly unflattering angle hail the arrival of this new and much-needed addition to the Memphis media market.