1. An apparatus for rendering graphical images by parallel processing, comprising: a plurality of processors, each processor comprising: model receiving means for receiving a model of an image, the model comprising a plurality of linked nodes, each node having associated therewith data representing an attribute of the image; node data receiving means for receiving node data corresponding to a change in the image; rendering means, coupled to the model receiving means, for rendering only a portion of the image corresponding to a subset of the plurality of linked nodes, the portion of the image comprising a plurality of pixels; a buffer comprising a plurality of buffer elements, each buffer element comprising: a first input terminal for receiving pixel data from a corresponding processor; an output terminal for outputting pixel data; a second input terminal for receiving pixel data from the output terminal of another buffer element; and multiplexing means, coupled to the first and second input terminals and to the output terminal, for selecting the pixel data from one of the first or second input terminals and for communicating the selected pixel data to the output terminal; wherein each of said processors renders only a portion of said image corresponding to the subset of the plurality of linked nodes thereof, and said processors operate simultaneously on different portions of the image.