GAUDY, GRITTY, SEXY, SPOOKY.... ONE 0F THE 21 RENDITIONS OF ELVIS SHOWN here will be the image for a postage stamp honoring the King due out early next year. Which one? First, two finalists will be named by a 13-member Postal Service advisory committee. Then, later this year, the public can give its own stamp of approval—by voting for one of those selections in a write-in campaign to be orchestrated by the Postal Service. As for the choices, "svelte and nonsvelte" is how Postmaster General Anthony M. Frank tactfully describes the young and aging Presleys pictured. "What you want to do," he explains, referring to El-vis's 50-lb. 2final years, "is avoid the word 'bloated.' " The stamp's eight commissioned artists have done just that: "Love Me Slender" is the predominant look. And by the way, the Elvis stamp must mean that the King really is dead. Explains Frank: "Being dead more than 10 years—that's a requirement.