"Stock photo" is what creative professionals call the photographs they use in their designs. A stock photo isn't shot for a particular ad or design - it's purchased from an existing collection because it happens to suit the designer's need. Hemera offers professional stock photos on AbleStock.com, Image Express, and packages other stock photos in The Big Box of Art family of products.
AbleStock.com has all the stock you need, from the bread-and-butter images most designers rely on, to textured background images shot in natural light, to highly conceptual art and composites.
an existing photo for which the photographer owns copyright