[CentOS] resize an image file

[Jerry Geis]

I have a 100G disk on an old redhat 7.3 system.

Filesystem            Size  Used Avail Use% Mounted on
/dev/hda1             9.6G  2.4G  6.7G  27% /
/dev/hda3              99G  6.1G   88G   7% /home
hda2 is 2G swap

I am trying to back that complete image up on my centos 5 system.
I can do the dd if=/dev/hda bs=1M | ssh root at machine 'cat > disk.img'
which gets me the whole 100G.

As you can see most of the disk is unused.
Is there a way to trim the resulting image to only be 10G instead of 100G?

Thanks,

Jerry