Stock images are professional photographs or illustrations that are available for licensing and use in various projects. They can be found in online libraries and are often used by businesses, marketers, and content creators to enhance their visual content without the need for custom photography. These images cover a wide range of subjects, including nature, people, business, and technology. By purchasing a license, users can legally use these images in advertisements, websites, and publications, saving time and resources while ensuring high-quality visuals.