An image includes at least first and second digital samples corresponding to first and second different color components. The image is compressed by detecting level changes of a first signal formed of the sequence of the first samples and by detecting level changes of a second signal formed of the sequence of the second samples. A determination is made as to whether the detected changes coincide with each other. The first signal is decimated. The compressed image that is output includes the decimated first signal, the second signal and a further signal indicative of coinciding detected changes.