The University of Mannheim, Germany maintains MATEO (MAnnheimer TExte Online). MATEO has Jean-Jacques Boissard’s 9 part Bibliotheca Calcographia, which is a 17th century who’s who photo album with a brief biography. The MATEO site has also done a favor for you by alphabetizing all 9 volumes of images (the alphabet bar) as well as present them in the same order as the original 9 volumes.
The Digitaler Portraitindex is also another great portrait resource, passed along to me by David Sytsma (congrats on the successful doctoral defense!) With the DPI you do need to check with the copyright holder for image usage details, some are covered under Creative Commons licenses others are more restricted according to the holding institution.