An apparatus and method for processing pictures (images, graphics or video frames) for image representation and comparison on the basis of a geometric feature description built from histograms of pseudo-color saturation. The feature description can also include normalized centroid variance, as well as an intensity map. The descriptions allow various matching comparisons to be performed between an input image and a set of comparison images, such as to find matching (or mismatching, or other relationship) images. The comparison can be sped using staged comparisons, whereby an image failing one level of comparison need not be considered in subsequent phases. A set of efficient image feature descriptors are described for use in a fast image retrieval scheme, which is efficient for searching of images spanning different image types, rotations and scales.