partimage
 

For some strange reason when I used partimage to backup my entire linux partition which is roughly 20 GB big it compressed to 12mb. Is this normal it doesn't sound right to GB. Am sure it's the right partition because it asked me to do umount /boot before it would work properly and it's the only ext3 partition on my HDD.

No, I'm sure that's not normal at all. Maybe try it again or try a different backup program.

please name any other alternatives

The documentation on http://www.partimage.org/ says that partimage does not copy free blocks.

For a full filesystem dump, use dd.

I know it doesn't it aint that though

Maybe the image is compressed?

I've only once tried partimage and that compressed the image with gzip.
There was also possibility to use bzip2, but it said that it takes much longer time and there is problem to restore MBR from image (if it's included).
I tested it to XP(ntfs) partition about 5GB and the image size was 3GB or something like that.

While 12MB does not really seem reasonable, try restoring the image to another partition and see what you get.

It's possible you may have some pre-allocated file space that has not been used yet.

CollieJim