For my brochure project ti chose to do it for the New York Public Library's Digital Collections, the website is full of many collections of photos, maps, documents, and illustrations. You can easily search for different topics, and download many images that are in the public domain. They also have a map tool that will allow you to overlay historical maps overtop of a current digital map. There is also a tool that allows you to manipulate stereogram images to create 3D images. There is a great amount of information that has been preserved and cataloged for easy access on the NYPL's website.