Download Art books:
Downloadable Art Books via the Guggenheim Museum
Downloadable Art Books via the Metropolitan Museum of Art
Downloadable Books via Getty Publications
Smarthistory via Khan Academy: Videos and clear explanations of the progression of art
WikiArt: Browse by time period, genre, style, medium (also an app)
The Artchive: Overview of various periods
Web Gallery of Art: Search by artist, period, style - take a guided tour
