1. A method of compressing a current image of a sequence of images, the method comprising the steps of: (a) transforming the current image with a predetermined transform to provide a set of transform coefficients; (b) retrieving, for at least one transform coefficient of the current image, one or more, but not all, bits of a corresponding transform coefficient of a previously compressed image of the sequence, wherein the corresponding transform coefficient is truncated at a truncation bitplane and the retrieved bits comprise the least significant bit of the truncated corresponding transform coefficient; (c) setting the at least one transform coefficient of the current image to a new value that is a function of the retrieved bits; (d) storing one or more, but not all, bits of the at least one transform coefficient for use in compressing one or more subsequent images of the sequence; and (e) coding the transform coefficients of the current image to provide a compressed bitstream of the current image.