1. A method for estimating compression noise in an image, said method comprising: receiving an image in a noise-estimation system; determining a first compression-noise estimate, wherein said first compression-noise estimate is associated with no scaling of said image; determining if said image has been scaled; when said image has been scaled, estimating a second compression-noise estimate, for said image, based on said first compression-noise estimate and a third compression-noise estimate, wherein said third compression-noise estimate is associated with a scaling of said image at a first scaling factor; and when said image has not been scaled, estimating said second compression-noise estimate, for said image, based on said first compression-noise estimate.