The NYPL Picture Collection Online
The Picture Collection Online is an image resource site for those who seek knowledge and inspiration from visual materials. It is a collection of 30,000 digitized, public domain images from books, magazines and newspapers as well as original photographs, prints and postcards, mostly created before 1923. It consists of images of New York City, Costume, Design, American History and other subjects.
http://digital.nypl.org/mmpco/