These images 140th Flag Day (or other media files) is in the public domain because its copyright has expired. This applies to the United States, where Works published prior to 1978 were copyright protected for a maximum of 75 years. See Circular 1 "COPYRIGHT BASICS" PDF. Works published before 1923, in this case 1917, are now in the public domain.
These 140th Flag Day images may however not be in the public domain in countries that figure copyright from the date of death of the artist (post mortem auctoris), in this case and that most commonly runs for a period of 50 to 70 years from December 31 of that year. This image may not be in the public domain in these countries, which moreover do not implement the rule of the shorter term to US works, If your use will be outside the United States please check your local law.
Title: 140th flag day, 1777-1917 The birthday of the stars and stripes, June 14th, 1917. Date Created/Published: 1917.
Medium: 1 print (poster) : lithograph, color ; 101 x 65 cm. Summary: Poster showing a man raising the American flag, with a minuteman cheering and an eagle flying above.
Reproduction Number: LC-USZC4-6262 (color film copy transparency)
Rights Advisory: No known restrictions on reproduction.
Call Number: POS - WWI - US, no. 412 (C size) [P&
and P] Repository: Library of Congress Prints and Photographs Division Washington, D.C. 20540 USA