Plasma polymer-silver composite films were deposited by simultaneous plasma polymerization of hexamethyldisilazane as well as benzene, and thermal evaporation of silver. The particle distribution of the silver particles in the insulating matrix was determined by transmission electron microscopy investigations. The changes of particle size and particle shape caused by laser annealing were investigated by image processing. The optical properties in UV/VIS/NIR were measured by transmission spectroscopy before and after laser annealing. Changes of the optical properties were modelled with effective medium theories concerning the changes of the microstructure.