ARTstor is the library’s primary visual resource collection, a collection of over one million images (as of September 2009), available to subscribers in medium-resolution format (for export), and high-resolution format (for on-line presentations or to download into ARTstor's own Offline Image Viewer). ARTstor contains a general collection ("The Image Gallery") and many specialized collections.
The Associated Press AccuNet Multimedia Archive contains "over two million photographs dating back to 1826, more than one million audio sound bytes dating from the 1920’s, two million Associated Press news stories from 1997, and a professionally produced collection of more than 45,000 maps, graphs, charts, logos, flags, illustrations, etc."
Oxford Art Online combines the contents of four resources: Grove Art Online, The Oxford Companion to Western Art, the Encyclopedia of Aesthetics, and the Concise Oxford Dictionary of Art Terms.
The Library of Congress' American Memory site offers over 9 million digital items (documents, photographs, maps, films, and audio recordings) from more than 100 collections. Copyright restrictions prevent reproduction of some images, but most of them may be used for educational purposes.
The libraries of the University of California present Calisphere, a selection of digitized primary sources designed to support K-12 instruction. "More than 150,000 digitized items — including photographs, documents, newspaper pages, political cartoons, works of art, diaries, transcribed oral histories, advertising, and other unique cultural artifacts — reveal the diverse history and culture of California and its role in national and world history."
The Libary's Digital Collections site contains a large selection of digitized primary sources from the Special Collection and Archives at the UC Santa Cruz Library.