“The Ford.” 1852. French. Oil on canvas. Collections of the Louvre, Paris. In the public domain in the United States because it was published before January 1, 1925. via https://commons.wikimedia.org/wiki/File:Constant_Troyon_-_The_Ford_-_WGA23096.jpg
“Pasture in Normandy.” 1852. Oil on panel. Collections of the Art Institute of Chicago. In the public domain in the United States because the artist died over 100 years ago. via https://commons.wikimedia.org/wiki/File:Pasture_in_Normandy_by_Constant_Troyon.jpg
“Boeufs allant au labour, effet de matin.” 1865. Oil on canvas. Collections of the Musée d’Orsay, Paris. In the public domain in the United States because the artist died over 100 years ago. via https://commons.wikimedia.org/wiki/File:Boeufs_allant_au_labour-Constant_Troyon-IMG_8342.JPG