By Oscar Holland, CNN (CNN) — When photographer Greg Brennan spotted Kate Moss in a fur coat at the bottom of a fire exit, cigarette in hand, he knew he’d stumbled across something special. The year was 2007, and what he didn’t realize is that one of the resulting photos — not even his favorite from the night — would become an emblem of the supermodel’s “party era” and the best-known image of his near-four-decade career. The mid-aughts photo’s e…