Ok, thanks, this is a time saver because we don't need to look at Acrobat any more; it isn't for server use.
Adobe have a C/C++ PDF Library which can do this (licensed by DataLogics), but it is not a quick or simple task to add an image; you'd have to parse the image file and convert to PDF internal representation to add it based on the PDF graphics model. Sticking on a PDF can be a bit simpler.