Depends on gimp >= 2.4.6 (not in the repo).
Should be rebuilt against 2.4.3 or 2.4.5.
It also seems like a big dependency for sane.
I know sane has a gimp plugin, but I wonder if it works fine without the gimp installed (even if it has been compiled with gimp support).
It that is the case, I guess the dependency should just be removed from slack-required.