Public Domain images are 'publicly available' and not covered by intellectual property or copyrights. There are many stock photography websites out there.
Free Images for Commercial Use - Free photos, stock photos, public domain stock photography.
All you wanted to know about public domain works - and why we can't expect new works until 2019 in the U.S.
Butterflies illustration of the Nouveau Larousse illustré, Adolphe Millot, public domain via Wikimedia Commons.
Public Domain - Vintage Postcard Images | Flickr - Photo Sharing!
Phrenology Diagrams from Vaught’s Practical Character Reader (1902) | The Public Domain Review
Animal - Sea shells and related - 6 | Vintage Printable
Different types of Washington quarters through the years. There are some Washington quarter issues that are rare or valuable. public domain photo
Diagrams showing the trajectory of the major dives as performed at the 1912 Olympics in Stockholm x
Vintage and Modern Free Public Domain Images Archive Download - Public Domain Images | Free Stock Photos