A method is for compressing a digital image including a matrix of elements, with each element including at least one component of a different type for representing a pixel. The method includes splitting the digital image into a plurality of blocks, and calculating for each block a group of discrete cosine transform (DCT) coefficients for the components of each type, and quantizing the DCT coefficients of each group using a corresponding quantization table scaled by a gain factor for achieving a target compression factor. The method also includes further quantizing the DCT coefficients of each group using the corresponding quantization table scaled by a pre-set factor, and arranging the further quantized DCT coefficients in a zig-zig vector.