Alexa here. One of my favorite places to look at images that give me a real sense of history is the Library of Congress Prints & Photographs Online Catalog. The catalog contains not only photographs but posters, prints, and architectural drawings. A search under the subject "motion pictures" yields some interesting results, including loads of architectural drawings of historic movie houses as well as fabulous images of Audrey Hepburn on the set of Sabrina, Monty and Liz entering the Palace Theater, Dumbo taking a bath, and Alfred Hitchcock and his wife visiting the pyramids. Prints can be purchased of any of the images from the catalog, and some images can even be downloaded free in high quality, suitable for printing yourself. Here are some downloads I made from the catalog today, showcasing many sides of the moviegoing experience in 20th Century America.
"Design proposal for a motion picture theater interior, possibly in New York City. Interior perspective view." 1935
"Man purchasing a movie ticket from a woman in a ticket booth as a couple stands to the side." 1958
"Negro going in colored entrance of movie house on Saturday afternoon, Belzoni, Mississippi Delta, Mississippi." 1939
"Where the boys spend their money." St. Louis, 1910.