I can't figure out why this always happens.

I want to center the image but it always ends up aligned to the left.

Code:
<body>
<h1 align="center">This site is under construction. Also, the internet is serious business.</h1>
<img alt="" longdesc="http://www.garbageartdumpsterbabies.com/images/dutchmastertransparency.gif" src="dutchmastertransparency.gif" />
</body>

The page is:

http://www.garbageartdumpsterbabies.com/disclaimer.html

Thanks in advance.