I read about this on ResearchBuzz.
First, do a Google Images search. Then add &imgtype=face to the result url. This means, go up to the address box and add the code to the end of that url that came back with your search results.
ResearchBuzz first searched on lightning and got 2 million images. After they added the &imgtype=face, it narrowed the results to 25,000. Faces doesn’t mean only human faces; it can mean animals, comic book heroes, bands … well, you get the idea.