A method of editing a digital image having associated embedded data, such as
printing
hints, includes embedding a first watermark in the original image before the image
is edited. The first watermarking scheme associates first watermark information
with each pixel and is used to detect which pixels have been edited. A second watermark
may be embedded in the original image according to a second watermarking scheme
which associates second watermark information with non-overlapping groups of pixels
in the original image. The second watermark information may be used to synchronize
the first watermark information and to detect editing information which does not
change pixel values. After editing, only those edited portions of the image need
have their embedded data reapplied.