The Oxford Encyclopedia of Ancient Greece and Rome offers a comprehensive overview of the major cultures of the classical Mediterranean world—Greek, Hellenistic, and Roman—from the Bronze Age to the fifth century CE.
This link takes you over 300 images of Greek vases from museums around the world. ARTstor has the best quality images of vases available. Another useful feature of ARTstor is that sometimes extensive notes on the vase are available.
This site provides many illustrations of vases from the Metropolitan Museum of Art collection of Greek Vases. Many of the images have text associated with it, but be careful, not all the text is authored by the Museum staff.