By the time the 60th Congress began, books with images of every Representative and Senator existed for decades. Publishers collected photographs of legislators and printed them collated by state. Some added major members of the executive branch, too. The books offered a handy way to identify Members of Congress on sight.
History, Art & Archives, U.S. House of Representatives, “Members of the House of Representatives Sixtieth Congress,” https://history.house.gov/Collection/Listing/2016/2016-054-000/ (November 12, 2022)
Office of the Historian
Office of Art and Archives
Attic, Thomas Jefferson Building
Washington, D.C. 20515
(202) 226-1300