The light transmission through metallic films with different types of nano-structures was studied both theoretically and experimentally. It is shown, analytically, numerically and experimentally, that the positions of the surface plasmon resonances depend on nano-structural details. This leads to a strong dependence of the amplitude of the light transmission, as well as the polarization of the transmitted light and other optical properties, on those details. Two complementary situations are considered: a metal film with dielectric holes and a dielectric film with metallic islands. Two different possibilities for manipulating the light transmission are considered: One is based upon application of a static magnetic field (actually, this is equivalent to changing the nano-structure in a transformed configuration space), the other is based upon using liquid crystals as one of the constituents of a nano-structured film.