ARTstor is a digital image library of approximately 700,000 images of art work, photography, and documents. You need to register (link on upper right) in order to download images.
NYPL: New York Public Library Digital Collections Website provides free access to over 800,000 images digitized from the NYPL collection. It includes posters, maps, photos, images from magazines, etc.
New Jersey Digital Highway presents resources of Seabrook Community's Japanese Americans, as well as other immigrant communities that setted in New Jersey. It includes documents, photos, publications, newsletters, etc.