The often published National Archives Photo #208-CN-3992 of President Franklin Delano Roosevelt addressing the United States Congress, in a joint session of the Senate and House of Representatives, has long been identified as the President delivering his war message on 8 December 1941, the day after the Japanese attack on Pearl Harbor.
However, a note with the original photograph states that the Franklin D. Roosevelt Library (Hyde Park, NY) has said that the view is not of that event. If that is the case, it may represent the 1941 or 1942 State of the Union Address, as the presiding officers (seated behind the President) are Vice President Henry A. Wallace and House Speaker Sam Rayburn. This photograph is from U.S. Office of War Information files in the National Archives.
If this is the case, the only true photo of FDR giving that war speech will only be a "still" from the film.