Image search engines are online tools that allow users to find images based on keywords or visual content. They work by indexing images from various websites and databases, making it easy for users to locate pictures that match their search criteria. Popular image search engines include Google Images, Bing Images, and TinEye. These engines often provide filters to refine searches by size, color, type, and usage rights. Users can upload an image to find similar visuals or use text queries to discover relevant images. This functionality is useful for research, inspiration, and creative projects.