CSS, background images & cell padding

[Michael Mishler]

Hello!

Can someone tell me why this code displays properly:

<style type="text/css" media="screen"><!--
body { color: #808080; font-family: "trebuchet ms"; }
#Table_01 { color: #f00; font-size: 80%; }
#maincell { background-image: url(images/splash_04.gif); vertical-align:
top; }
--></style>

see here: download.mishlercomputers.com/shouldbe.jpg

and this code causes the background image to be approximately 20px too wide
causing the image to repeat it self:

<style type="text/css" media="screen"><!--
body { color: #808080; font-family: "trebuchet ms"; }
#Table_01 { color: #f00; font-size: 80%; }
#maincell { background-image: url(images/splash_04.gif); vertical-align:
top; padding: 20px; }
--></style>

see here: download.mishlercomputers.com/problem.jpg

The browser I'm seeing this in, is IE7.0 and checked it on IE6.x as well

if you want to look at the HTML, etc. the URL for this is:
http://download.mishlercomputers.com/splash/splash.htm

Thanks very much for any input on this!
Michael