1. A method for reducing the spacial resolution of an image comprising an original pixel array, each pixel characterized by luminance or color values, by transforming said original pixel array to a final pixel array having fewer pixels, comprising: transforming said original pixel array into a transformed spectral array, each entry of said transformed spectral array identifying spectral components in spacial variation of luminance or color values of pixels of said original pixel array, inverse transforming said transformed spectral array to generate said final pixel array having fewer pixels, the luminance or color values of pixels of said final pixel array having a distribution of spectral components of spacial variation similar to low order spectral components of said original pixel array, but not including high order spectral components present in said original pixel array, and multiplying each entry in one of said original pixel array, said final pixel array, or said transformed spectral array, by a factor equal to the square root of the ratio of the number of pixels in said final pixel array to the number of pixels in said original pixel array, to compensate for increases in image brightness resulting from the reduced number of pixels in said final pixel array.