pkladisios, i asked "do you mean A, B or C?" and you answered "Yes"...
anyhow, whether you use inkscape or something else (pdfimages sounds like a sane choice to me), you have to start reading some documentation and find out what the software actually does. i'm sure it will tell you whether it lossily transcodes the images on the fly, or whether it extracts the actual images as they are.
and forget about gimp for this one.
always remember: in gnu/linux, the software is on YOUR side. you don't have to work against it; you can work WITH it.