Amsterdam's Rijksmuseum https://www.rijksmuseum.nl is a free, online archive of 125,000 high resolution images. Each image gives you the ability to zoom in, making it possible to examine the individual brush strokes in the eye of van Gogh's famous self portrait. This type of access and ability to examine details make this collection very useful for art students. Social media tools are built in, so you can "like" a photo (and the museum). The collection, which includes works by Rembrandt, Vermeer, Mondrian and van Gogh, has already made images of 125,000 of its works available through Rijksstudio, an interactive section of its Web site. The museum hopes to add 40,000 high res images a year the library, according to the New York Times http://nyti.ms/1465viS.