The features of magnetic-microstructure imaging were studied using various configurations of dark-field magnetooptical microscopy. The potentials and limitations of the dark-field method were experimentally and theoretically analyzed as applied to magnetism studies. The experimental data showed the possibility of magnetooptical detection of localized magnetic structures of size smaller than or of the order of 0.1 μm. To calculate the angular spectrum of light scattered at magnetic inhomogeneities within a theoretical model, the method of electrodynamic tensor Green functions was employed. Within the theoretical model, a procedure was proposed and analyzed which allows real-time visualization of magnetization reversal of solitary single-domain nanoparticles or their regular arrays in order to study their dynamic and static characteristics.