1. A method of displaying, on a subpixel addressable screen of an image displaying device having pixels comprised of separately-addressable, differently-colored subpixels, digital content including text and/or images represented by a mark-up language including tags that dictate the format in which such content is to be displayed and tags that identify images to be displayed as part of said content, said method comprising: accessing said digital content, including accessing one or more images, from one or more devices in which said content is stored or is generated dynamically; performing a down-scaling and subpixel-optimization process in which: each of said accessed images is a source image for the process; said process produces from each such source image a corresponding scaled-down, subpixel optimized image; each such scaled image represents the source image from which it has been produced at a lower pixel resolution than the pixel resolution of said source image; each such scaled image also represents the corresponding source image in a subpixel-optimized manner by causing the luminosity associated with each subpixel within a given pixel of the scaled image to represent the luminosity of the subpixel's color in a portion of the corresponding source image that differs for each subpixel as a function of the subpixel's different position in the given pixel; and displaying said accessed digital content on said subpixel-addressable screen in a format determined at least in part by one or more tags in said content, including, as part of said formatted display, displaying said scaled images in a subpixel-optimized manner on said screen; wherein: said accessed digital content includes one or more strings of displayable text characters; and said display of said digital content also includes drawing a string bitmap on said screen to represent said string, the string bitmap being composed from a succession of separate font bitmaps each selected to correspond to an individual character in the text of said string; said font bitmaps are anti-aliased subpixel-optimized images of character-font shapes; and said subpixel-optimized character-font shape images are subpixel-optimized in a different manner than the scaled images in that: the luminosity assigned to each given subpixel of a pixel in one of said scaled images represents the intensity of the given subpixel's corresponding color in a portion of the source image having a position corresponding to the position of the given subpixel in the scaled image; and the luminosity assigned to each given subpixel in one of said font bitmaps is a function of: a coverage value representing the percent of the given subpixel's area in the font bitmap that is covered by the character-font shape represented by the bitmap; and for at least some subpixels of said font bitmaps, a color balancing distribution between the given subpixel's coverage value and coverage values of other nearby subpixels that reduces perceptible color imbalances that would result from differences between coverage values of nearby subpixels of different colors in the absence of such color balancing distributions.