The paper considers the possibility of using a mosaic composed of many miniature images to hide the fact of text information transmission. The results of the study of optimal mosaic construction when using steganographic methods of hiding information are presented. The use of the proposed algorithms implies the use of сryptographically secure pseudorandom number generator with dynamically changing parameters for concealing information. The generators are used to determine the location of information bits in a certain mini-images, as well as in a specific pixels and color channels. Using the proposed algorithm, no more than twenty-five percent of the color channels are changed, provided that one bit per color is used. This paper is supplemented with illustrations and examples of how the algorithm works.