ways to speed up imaging?

Hi,

I'm wondering if there are any effective ways to speed up the amount of
time it takes for images to complete. Images are taking anywhere from 35
minutes to approaching an hours to make and the final file size is just
over 4 gigs at its largest. Since upgrading to a gigabit switch for the
servers I can take two images at the same time, before they would both
freeze if two were attempted. Also, it takes over 15 minutes to copy a
final image file from one server to another, even though they are attached
to the same gigabit switch. The filesystem of the zenworks server is NFS.
The workstations are an aged spec with either AMD 2200+ or 2600+ and
either 256mb or 512mb of ram with standard XP pro installs, office,
antivirus, groupwise, and a handful of job specific applications.
How can we speed this operation up!!

thanks,

Luke