When searching for images of the Nationality Rooms, one can look in several places. 

While you use the books and journal articles for your research, make a note of images that are related to your topic and can illustrate the points you make about it.  Note in what books they were found (title and call number to re-locate the book and page number so you can relocate the illustration) and also what journal articles had useful images (title of the journal, date, and page number).