Primary Sources Online
ArtStor
A huge repository of images from museum collections, such as this slave's face jug from South Carolina
Food Studies Online
This collection of digitized sources includes cookbooks, menus, recipe books, marketing pamphlets, posters, vintage commercials, and other ephemera.
The Art of American Advertising, 1865-1910
An online exhibit of 19th-century trade cards and other advertising ephemera, drawn from the collection of the Baker Library at the Harvard Business School
The Internet Archive
Using the Advanced Search, combine your keywords with the mediatype Image to find historical images of products and other objects. You can narrow the results by date and topics such as "Advertising Art in Magazines."