Back Ground (watermark) Image for Page templates

[mediaguru]

I searched for this and could not locate a definitive answer.

Client has asked me to put a water mark or back ground image on certain pages. I think the best way to accomplish this would be to set this up as a page template however, I do not see an easy way in PHP to be able to add in a background image, much as you can with html.

Can this be done without modifying or calling the style sheet into play ?

We just want a single image either in the center or preferably the lower right corner of the page to take up some of the white space on certain pages, but we don't want it selectable.

Any ideas on how this can be accomplished would be much appreciated. :D