I would try it. I saved it as a .JPG image. If anyone can't display this let me know. It was a little tedious but it worked. But it does look good.
Graphics objects that is.
GIMP will deal with individual image planes and overlays quite easily. You can even load in another image overlay from a file to include it in with the current set. I've heard of people using it for laserprint PCB artwork. I'm no expert on GIMP, but from what I've done sofar I'd see no problems with it being used to edit schematics. Only allow a link to be posted.