Cecco Bravo art links 

Art Institute of Chicago   NEW!
Standing Male Nude

Kress Foundation Collection   NEW!
(Look for the "Image" links for super high resolution scans)
Angelica and Ruggiero, ca.1660

Louvre Museum Graphic Art Database, Paris (in French)   NEW!  

Rijksmuseum, Amsterdam   NEW!
Great scans of Rijksmuseum paintings, from the 'Memory of the Netherlands' project

Rijksmuseum Research Database, Amsterdam (in Dutch)  

Cleveland Museum of Art, Ohio

Harvard University Art Museums, Massachusetts

Palazzo Montecitorio, Rome (mostly in Italian)  
L'Aurora

Philadelphia Museum of Art
(Tip: On the zoom-in page, use the slider bar to magnify the image)
Landscape with Figures

State Museums of Florence Digital Archive, Italy

 
National Art Databases and Museum Inventories:

UK National Inventory of Continental European Paintings (NICE)   NEW!

 

Bildindex der Kunst und Architektur (in German)  
(a welcome screen is displayed for a couple of seconds before the search results appear)

 

Grove Dictionary of Art Online (excerpt)  

Union List of Artist Names (Getty Museum)  
Reference sheet with basic information about the artist and pointers to other references.