Method for lossy compress-encoding image data, said method comprising - modifying quantized coefficients of a transformed residual of a prediction of said data for minimizing rate-distortion cost, wherein the data and the quantized coefficients are arranged as two-dimensional blocks, and wherein distortion is determined using a post-processed reconstruction of the data, the post-processed reconstruction being post-processed according to a post-processing method, and - compress-encoding said modified quantized coefficients, wherein - the post-processing method is that one of n>1 different predetermined post processing method candidates whose position in a predetermined order of arrangement of the post processing method candidates equals a remainder of division, by n, of a sum of the modified coefficients; and - modifying the coefficients comprises: - determining a sequence of coefficients by: o scanning the quantized coefficients according to a scan order and using the sequence for determining those quantized coefficients which each: • represent a frequency above a predetermined frequency threshold, • do not exceed a predetermined positive threshold, and • are the only non-Zero coefficient contained in contiguous subsequence of at least a predetermined positive number of quantized coefficients, and - identifying, among the determined coefficients, those which, when set to zero, lead to minimization of rate-distortion cost and setting the identified coefficients to Zero, wherein the reconstruction is determined using said modified coefficients and said prediction, said prediction being determined using already compress-encoded data and a reference to the already compress-encoded data is further compress-encoded. - modifying quantized coefficients of a transformed residual of a prediction of said data for minimizing rate-distortion cost, wherein the data and the quantized coefficients are arranged as two-dimensional blocks, and wherein distortion is determined using a post-processed reconstruction of the data, the post-processed reconstruction being post-processed according to a post-processing method, and - compress-encoding said modified quantized coefficients, wherein - the post-processing method is that one of n>1 different predetermined post processing method candidates whose position in a predetermined order of arrangement of the post processing method candidates equals a remainder of division, by n, of a sum of the modified coefficients; and - modifying the coefficients comprises: - determining a sequence of coefficients by: o scanning the quantized coefficients according to a scan order and using the sequence for determining those quantized coefficients which each: • represent a frequency above a predetermined frequency threshold, • do not exceed a predetermined positive threshold, and • are the only non-Zero coefficient contained in contiguous subsequence of at least a predetermined positive number of quantized coefficients, and - identifying, among the determined coefficients, those which, when set to zero, lead to minimization of rate-distortion cost and setting the identified coefficients to Zero, wherein the reconstruction is determined using said modified coefficients and said prediction, said prediction being determined using already compress-encoded data and a reference to the already compress-encoded data is further compress-encoded. - determining a sequence of coefficients by: o scanning the quantized coefficients according to a scan order and using the sequence for determining those quantized coefficients which each: • represent a frequency above a predetermined frequency threshold, • do not exceed a predetermined positive threshold, and • are the only non-Zero coefficient contained in contiguous subsequence of at least a predetermined positive number of quantized coefficients, and • represent a frequency above a predetermined frequency threshold, • do not exceed a predetermined positive threshold, and • are the only non-Zero coefficient contained in contiguous subsequence of at least a predetermined positive number of quantized coefficients, and - identifying, among the determined coefficients, those which, when set to zero, lead to minimization of rate-distortion cost and setting the identified coefficients to Zero, wherein the reconstruction is determined using said modified coefficients and said prediction, said prediction being determined using already compress-encoded data and a reference to the already compress-encoded data is further compress-encoded. minimization of rate-distortion cost and setting the identified coefficients to Zero, wherein the reconstruction is determined using said modified coefficients and said prediction, said prediction being determined using already compress-encoded data and a reference to the already compress-encoded data is further compress-encoded.