The 100-some dresses Patrick Demarchelier photographed for “Dior Couture” (Rizzoli, $115) constitute a high-gloss tribute to the venerable fashion house. But the book is also a curiously timed retrospective of Dior’s fallen creative director, John Galliano, who designed the bulk of what’s included here. Demarchelier dusted off frocks by Dior and his successors, Yves Saint Laurent and Marc Bohan. (Gianfranco Ferré, who was creative director from 1989 to 1996, is left out.) The foreword is by Jeff Koons — a Dior fan, apparently — who sees the couture pieces as “reminiscent of a spider’s web, mirroring nature.