I've used Alchemy or ImageMagik to do deal with PDFs, but was in Linux. Another option would be to hit print screen (print screen copies what you're looking at into your paste buffer, there are also other variations like alt + prnt scrn to only copy the current window) and paste it into an image editor to modify and safe to whatever format you want. I would probably go for a loss-less compression (like a GIF) if they are only black and white. I am sure there is other software out there that can export the pages from a PDF into some other format.
Pete