You could also extra images with your pdf reader, I use a free version of nitro reader so i can just hit the "extract all images", you'll have to sift through some filler stuff used for the pdfs borders and whatnot though (pretty easy if you open up the window and set files to large image). Also you should be able to right click on an image in a pdf with most readers and click "copy image". I like gimpshop for some things, but I prefer to use paint for doing simple image edits as gimpshop seems to inflate the file size of jpegs I save with it (definitely great for making maps from scratch though. Or making tokens :D )