The application of the H-1 NMR microimaging technique to the indirect mapping of the spatial distribution of hexachloroplatinate dianion within porous alumina pellets is reported. It is demonstrated that the nuclear spin-lattice relaxation times of liquids filling the pores of the pellet increase in the presence of the adsorbed hexachloroplatinate dianion, The microimaging results for the supported catalysts with two types of platinum distribution (egg-shell and egg-white) are shown to be consistent with the results obtained by the staining method and electron probe microanalysis. Finally, the microimaging technique is employed for a nondestructive visualization of the dynamics of the active component redistribution in the course of the supported catalyst preparation by competitive adsorption.