1. A method of processing an array of image data, comprising: processing tiles of the image data in a predefined order, the tiles comprising nonoverlapping portions of the image data, so as to generate processed image data; and storing the processed image data as a data image file; the processing of each tile in a first subset of the tiles of image data comprising: applying a predefined sequence of transform filters to the tile of image data so as to generate successive sets of transform coefficients; and saving a copy of predefined sets of edge transform coefficients from a corresponding plurality of the sets of transform coefficients for use while applying the predefined sequence of transform filters to predefined tiles neighboring the tile being processed; the step of applying a predefined sequence of transform filters including, for a second subset of the first subset of tiles, applying each of a plurality of the transform filters to both the set of transform coefficients generated by a prior transform filter and the copy of a set of edge transform coefficients saved while processing a predefined neighboring tile.