A system and method for optimisation of media objects for delivery to one of a plurality of mobile communication devices of different types and rendering thereon. In particular, the media objects are optimised according to the mobile device's characteristics to ensure efficient delivery and optimal rendering thereon. For this purpose, an optimised output of the media object is determined at a first stage. At a subsequent stage, based on the mobile device type, the characteristics of the object to be delivered are then adjusted to conform to those of the predetermined optimised output, thus ensuring that the rendering of the optimised media object on the mobile device output is of high quality.