The best tool for image-related scholarly research is ARTstor. However, ARTstor has rules about how images can be used - you can use them in your homework, presentations, password-protected education websites (Canvas), and personal use (inspiration). You cannot post them on the open web or use them for profit.
To save or download images from ArtStor you must build an account while on campus. Click on "Enter ArtStor Digital Library" then use the "Log In or Register" link in the upper right. If you get stuck, contact your librarian: firstname.lastname@example.org.
There are number of ways to get free images online. However, you cannot be certain those images are accurate. Below are some free online sources for images from trustworthy sources.
The images found at these sites work well for art projects. Use them for research and scholarly papers only if you can verify that they are from a reliable source and have not been edited.
When using images for non-educational work, there are rules in place to protect the creator of the original image. The best thing to do is to find images through Creative Commons that allow modification.
Just like with the text resources (articles, books, websites) that you use, images have to be cited. Use the information below to cite your images in either MLA or Chicago (whichever style you use for your text should also be used for images).
You will need:
Klee, Paul. Twittering Machine. 1922. Museum of Modern Art, New York. ARTstor. Web. 22 May 2006.
Rogier van der Weyden, Saint Catherine of Alexandria. 1430-1432, Diptych panel, 18.5 x 12 cm. Kunsthistorisches Museum, Vienna, Austria. Available from: ARTstor, http://www.artstor.org (accessed September 30. 2009).