title: Adding image annotations to pdf with ghostscript
body: <p>I would like to use ghostscript to add an annotation to a pdf file, similar to the method described <a href="https://stackoverflow.com/questions/4427034/add-comments-to-pdf-files-automagically-with-regular-expressions">here</a>.  However, instead of a text annotation, I want to add an image as an annotation.  Given what I have read in the pdfmark reference and the pdf reference, I think it should be possible by inserting a "custom" rubber stamp annotation.  If anyone could provide an example of how to do this, I would be very appreciative.</p>