CSS and background picture

I have a picture, which I want to use as background. How do I define this in CSS?

Code:

---

background : techlogic_vandmaerke.gif;

---

<style type="text/css">
body {background-image:url(techlogic_vandmaerke.gif);}
</style>

Or

<style type="text/css">
body {background:url(techlogic_vandmaerke.gif);}
</style>

And that'll work for any box, not just the body tag!