Where does the budget concious art teacher go to expose her students to centuries of great art? Well, there’s a lot of places, but one of the websites to start at would be the Web Gallery of Art. The museum claims to have the digitized works of most major painters (and a lot of minor ones) from about 1100-1850. I don’t know if the claim is true, but there is an awful lot of images there to study and learn from. This could prove to be a very useful resource if you’re looking at the history of art.