Theoretical and practical bases of multimedia data processing using computer steganography, as well as methods of steganographic analysis of graphic content of info-communication systems are considered. Illustrates how Mathcad's universal math system can be used for steganographic processing. Examples of practical implementation of data hiding in static images, audio signals and text are presented. The problems of reliability and stability of an arbitrary steganographic system in relation to various types of attacks, as well as estimates of the bandwidth of the hidden data exchange channel, are systematically described. The results of information and practical research of the problem of steganographic analysis of digital images are presented.