Webpage background question

I am creating a webpage. I’ve imported a bitmap image for use as the background image and would like extend it ‘indefinitely’ beyond the stage are so that when I open the html file in a web browser, there is no visible ‘white’ area. In other words, I don’t want a visible border. (please see http://newyork.mets.mlb.com/index.jsp?c_id=nym repeated background image as example)

I’ve looked at tutorials talking about tiling images but I don’t think this is what I’m looking for.

Any suggestions are appreciated.
Thanks!