How is this background image placed?

programming flash
1

In researching some great Flash based sites, I started to wonder if the bitmapData class can be used to place a background image similar to how a background image is placed using CSS.

Take a look at the Letters for Iwo Jima website, which is pretty smooth by the way:
http://iwojimathemovie.warnerbros.com/lettersofiwojima/framework/framework.html

Is this site entirely in Flash?
If so, how was the background image placed? (assuming the width of the top nav menu is the full width of the stage)

Second, on the About The Film page, the text block stretches down vertically, again past what I would assume would be the stage.

I can’t seem to think outside the box (stage), as it were. I’d appreciate ANY insight on this!

thanks!