Depending on the desired image, the copyright may be expired due to the age of the image. In the US, copyrights of images published before are expired. This also applies to many old paintings and photos. Such images can be safely used for Wikipedia even if there is a copyright notice on the page. There are also other ways around a copyright, for example but this is a legal minefield and should be avoided if possible . Historic photographs are almost always grayscale, so you can speed up your search by using an advanced image search with the limitation to Return only images in grayscale.