A method and apparatus are described for performing header-based scaling
and cropping of images compressed using multi-scale transforms. In one
embodiment, the method for adaptively scaling an image comprises
receiving a file containing a header that contains multi-scale entropy
distribution information on blocks of an image; for each block,
determining that the block retains significance at a scale upon
determining that an entropy of a multi-scale coefficient of a block at
the scale is greater than a mean entropy of multi-scale coefficients of
blocks in at least one coarser scale; and scaling the image to a coarsest
scale at which a threshold percentage of the blocks retain significance
at the scale.