Does it save disk space using a grouped image as a background?

[Stgoldberg at aol.com]

If an image is going to appear on many cards and one wants to save disc 
space, I found the advice very useful from the forum to use the image as an icon. I 
was wondering whether or not it may also save disc space to group the image 
and set it to act as a background. For instance if I have an image that I'd 
like to use as a button to appear on many cards, if I set it to act as a 
background, will it use less disc space than if I did not set it to act as a 
background? Or would I need to import it as a "referenced control" in order to conserve 
disk space?   Thanks.
Steve Goldberg