ASP image map and HTML image map acts different

Hello,
When i use the regular html image <map> tag my gap disappears right below the header. But I want to stick to the asp:imagemap tag. When i use the asp version of image map it leaves a white gap below my banner. As you can see here: http://www.tpham.net/testing/
Here's my code for the image map:
<asp:ImageMap ID="ImageMap1" runat="server" HotSpotMode="Navigate" ImageUrl="~/images/headerBanner.jpg" Width="838" Height="114" BorderStyle="None" CssClass="test"><asp:RectangleHotSpot Top="0" Bottom="225" Left="0" Right="150" /></asp:ImageMap>
Is there a way to get rid of that white space?
 
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