The Revs Digital Library website contains nearly 200,000 images of automotive history (as of January 2015). As with other digital library sites, users can search and browse to find content that interests them.
A search engine, however, is only as good as the data being searched on. Since the website will eventually have over a million images, browsing to find the images you want is not a great option and good information about the images becomes critical. Interested in Porsches? Chevy's from the 1960s? Mario Andretti, but only when he drove in the Indy 500? All of these wonderful ways to find materials are dependent on having metadata, or information about the images.