Can I define a table width/height to be the same as the visible client area of the browser?

My plan is to display a graphic right in the middle of the screen using something like

<table width="width of visible client area" height="height of visible client area">
<tr>
<td align=center valign=center>
<img src="graphicfile.jpg" blah blah blah>
</td>
</tr>

Or is there a better method of doing what I want?