A good choice for annotation is TeX, specifically LaTeX in conjunction with the LaTeX package pdfpages, and the drawing package TikZ. An example script follows. This is the overlay of the two page document text.pdf. The command \includepdf from the pdfpages package is invoked with the pagecomman...

Is it possible to resize an image in an answer? For example, How important is PhD research topic to getting a job? has an answer that should have the image in the answer, but it's too big. Is there a way to handle resizing?