Weegee: Naked City (Steven Kasher, 521 W. 23, up through Feb. 25). A compact and atmospheric exhibition of 125 prints by America’s greatest tabloid news photographer. Sad, sordid, appalling, and electrifyingly exciting, these hard-edged black-and-white images capture the essence of New York in the Thirties and Forties, instant by instant (TT).