<center><img src="blah" /></center> if you want to use deprecated tags.
The PROPER way to do it is
<style type="text/css">
img.center {
display:block;
width:auto;
height:auto;
}
</style>
That goes in the header.
This goes where you want the image to go:
<img class="center" src="blah" />
Make sure to replace "blah" with the URL you want.
