1. A method of dithering pixels of a graphical representation, the method comprising the steps of: receiving the graphical representation subdivided into a plurality of portions, each portion comprising a plurality of regions, each region being associated with an attribute type corresponding to content of the region; combining adjacently located regions associated with a same predetermined attribute type within a portion, to form a merged region; comparing a size of the merged region with a threshold for the predetermined attribute type to select a processor for dithering at least the merged region, the processor being selected from a plurality of processors comprising at least a central processing unit and a graphics processing unit; and dithering pixels of the graphical representation using at least the selected processor.