Vogue’s upcoming exhibit at the Metropolitan Museum of Art promises to be bigger than ever. Astonishing new photos from the upcoming “Costume Art” show — timed to the eagerly anticipated Met Gala on May 4 — reveal an array of wild designs, hanging on an eyebrow-raising collection of supersized mannequins. Instead of relying on the traditional sample size of two, the exhibit eagerly celebrates a wide range of shapes, including pregnant, disabled and aging bodies — reflecting a shift playing out