1. A method of preparing image data comprising a plurality of data values for compression, the method comprising: identifying locations of one or more data values of a first subset of data values; subjecting the image data to a forward wavelet transform that generates transformed image data that includes at least one coefficient associated with each respective data value; replacing the at least one coefficient associated with the one or more data values of the first subset with respective replacement coefficients; and subjecting the transformed image data including the replacement coefficients to an inverse wavelet transform to generate modified image data.