License, verbatimPD
The National Gallery of Art: open access image with no usage restrictions under the NGA's open access policy (openaccess=1 in the Gallery's published_images dataset).
Eadweard Muybridge. Plate Number 491. A, B: Hammering at an anvil. C: Using a hatchet. D: Sawing a board, 1887. National Gallery of Art, Washington.