From coprightlaws.com
"Are You Using Copyright-Protected Images?
More and more we are using images to enhance text-based documents, annual reports, websites and blogs. As a universal rule, most images are protected by copyright laws around the world and permission is required to use the image as is, or to adapt it. Let’s look at some of the specifics surrounding this general rule.
Images may be defined in various manners. Under the U.S. Copyright Act, images of various sorts are called “pictorial, graphic, and sculptural works”. These works are defined to “include two-dimensional and three-dimensional works of fine, graphic, and applied art, photographs, prints and art reproductions, maps, globes, charts, diagrams, models, and technical drawings, including architectural plans.” So illustrations, photographs, charts and the like, are all protected by copyright.
The full range of rights attach to owners of these works. The owner of copyright has the exclusive rights to do and to authorize the reproduction of the images, prepare new works based on the original works, distribute copies to the public by sale or other transfer of ownership, or by rental, lease, or lending; and to display the works in public."
Note: permission is required to adapt it.
What really irks me is to find one of my images on Google attributed to someone else, which has happened twice already.