The analysis of digital images having complex structure includes the application both processing methods and mathematical algorithms. As a rule, the processing helps to find the representation of an image which is more suitable for application of mathematical methods. Depending on the type of images the obtaining of an appropriate presentation may be the essential part of the study. In the paper we apply the application of fractal and multifractal methods to compare crystals of medical preparations with a control image which does not contain a preparation (placebo).The images under study were prepared for analysis by a special program and transformed to grayscale palette. For several classes containing 5-6 images the applied methods demonstrated the separation of obtained characteristics, which means the difference in structures of medical preparations and placebo.