I have the same question, as I am modifying images and want to show them over the original and give the user the option to accept or reject.
I am using Image Magick as the image mod engine, and it has a com object you can use instead of running it through a shell command.
I have replaced adesk's Raster Design using this approach, though we do not use the image "snapping" or tracing abilities it has, because its just as fast to pick by hand in my experience. Raster design is a nice tool, I just wanted something that ran in bcad and handled large images better than RD. Bit off track from the OP but might be useful.