2 pixel column height discrepancy in IE 6

Hi all,
I've searched the forum for a similar problem but can't seem to find anything.
I have a 2 column floated layout that works well in the usual suspects apart from IE 6 where the left column is 2px deeper than it should be i.e. it's 502px not 500px.
It appears to be something to do with the images I've used since, when they are removed it works fine.

Can anyone help?

Thanks
Yan

css

body {
margin:0;
font-family: Verdana, Helvetica, Arial, sans-serif;
font-size: 0.5em;
line-height: 1.5em;
letter-spacing: 0px;
text-align:center;
}


#frame {
width: 750px;
height: 500px;
margin-right:auto;
margin-left:auto;
margin-top: 15px;
padding: 0px;
text-align:left;

}
#thumbpanel
{
float: left;
padding: 0;
width: 210px ;
height: 500px;
background-color: #877F68 ;
overflow: hidden;

}

p {
margin-left: 0px;
}

/* Hide from IE5-mac. Only IE-win sees this. \*/

* html #thumbpanel {
margin-right: 0px;
}

* html p {
height: 1%;
margin-left: 0px;
}

/* End hide from IE5/mac */

#nav
{
float: right;
width: 540px ;
height: 56px;
background-color: #191414;

}

#content
{
float: right;
width: 540px ;
height: 444px ;
background-color: #191414;
}

#img_portrait
{
position: relative ;
width: 498px ;
height: 370px ;
margin: 0 auto ;
border-style: solid ;
border-width:2px ;
border-color: #fff;
top: 33px ;
}

#navcontainer ul
{
position: relative;
top: 32px;
margin: 0;
padding: 0;
list-style-type: none;
text-align: center;
}

#navcontainer ul li { display: inline; }

#navcontainer ul li a
{
text-decoration: none;
padding: .2em .8em;
color: #fff;
}

#navcontainer ul li a:hover
{
color: #fff;
/*background-color: #369;*/
}

#toprule
{
position: relative;
top: 20px;
border-top-style: solid;
border-top-width: 1px;
border-top-color: #fff;
}

#bottomrule
{
position: relative;
top: 12px;
border-top-style: solid;
border-top-width: 1px;
border-top-color: #fff;
}

#tagline
{
height: 81px;
width: 210px;
position: relative ;
top: 353px ;
}

#logo
{
height: 63px;
width: 210px;
position: relative ;
top: 0px;
}

html

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