This site lists art galleries by type and genre, art distributors and publishers
Artnet.com:This site is an Internet portal to the world of art. It is a premier site on the web for art content and e-commerce. It provides online auctions, member gallery and artist sites, magazine, bookstore, art research tools and resources. Artnet.com AG is a public company traded on Germany's Neuer Markt.
The Artists Bluebook: This site claims to be the most comprehensive database dedicated to American Artists. Images and information on books, articles, museum holdings, auction records, graphical sales analyses, and more, are dedicated to each of the 25,000 artists spanning the 16th to the 21st centuries. The images are included for commercial purposes. They are useful for identifying artists' works, but are only of fair quality.