multiple images and cloning

I know that multiple images can be stored on a linode. What I haven't seen, however, is a way to make a copy of an image. What I'd like to do is shrink down my current image to half the available space on my linode and duplicate it so that I can make some changes and be able to fall back to the old image if things don't go well.

Is there any way to do this on my own?