The document describes content-based image and video retrieval (CBIR) algorithms. It discusses how CBIR works by extracting features from query images, indexing images, and retrieving similar images based on color, shape, and texture features. CBIR techniques include reverse image search, semantic retrieval using queries, and relevance feedback to refine searches based on user input about retrieved images. The document provides examples of CBIR applications in areas like crime prevention, military, web searching, and medical diagnosis.