You can always stretch an image so that it will fill an entire space, but this can look weird on big monitors and may not work properly across all browsers. That’s why most designers prefer some kind of tiled background image. One way to avoid weirdness is to set your background image to “fixed” rather than “scroll”. Improves appearance tons.
You have a labyrinth…very nice. A very nice website all around. Best of luck in your endeavours!