Wikimedia Commons is basically an international, open-source media repository. Media of all description (pictures, graphics, video and audio) are posted by the users/members; most works are original...
Because notification is not required for protection, its safest to assume that any image you encounter is protected unless specified or proven otherwise. NASA imagery is one notable exception, and...
Any image appearing online would be protected by copyright unless specified otherwise. For example, some flickr users choose Creative Commons licenses, and others (often public libraries) specify the...