This course will give an overview of the main tasks and methods in the content based image retrieval (CBIR) field. Firstly we will address a question of image retrieval methods application in real life: what are the real-world problems that can be solved using these methods, where it can be used by human. Then we will consider the traditional architecture of CBIR-systems and the main problems which should be solved by the developers of such a system. This includes the discussion of image preprocessing and feature extraction, multidimensional indexing, design of user interface and data visualization. Special attention will be given to low-level feature processing (color, texture and shape) and construction of feature vectors. The classification of known feature vectors will be presented and results of experimental comparison will be discussed for some of them. In the final part of the course we will briefly review some of the existing CBIR systems (both commercial and research ones) and we will analyze and discuss their advantages and disadvantages.