Proba poniendo body {
margin:0;
}
tambien puede ser overflow: hidden;
y sino proba como tengo en mi web:
te paso el codigo, es CSS play.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title> stu nicholls | CSS PLaY | 100% wide/high 'background' image emulation </title>
<meta name="Author" content="Stu Nicholls" />
<meta name="Keywords" content="cssplay, css play, Cascading, Style, Sheets, CSS1, CSS2, CSS, XHTML1.1, w3c, doing it with style, recommendations, opacity, box model, mozilla, opera, netscape, internet explorer, v6, v7.23, techniques, layout, three column, cutting edge, experimental, validation, validate, navigation, pop-up, pull-down, menus, tips, tricks, css mouseover, mouseovers, CSS experiments, CSS demonstrations" />
<meta name="Description" content="CSS ~ Cutting edge Cascading Style Sheets. Experiments in CSS" />
<meta http-equiv="imagetoolbar" content="no" />
<link rel="shortcut icon" href="../favicon.ico" type="image/x-icon" />
<link rel="icon" href="../favicon.ico" type="image/ico" />
<style type="text/css">
html, body {
margin:0;
padding:0;
width:100%;
height:100%;
overflow:hidden;
text-align:left;
}
body {
font-family:verdana, arial, sans-serif;
font-size:76%;
}
#background{
position:absolute;
z-index:1;
width:100%;
height:100%;
}
</style>
</head>
<body>
<div>
<img id="background" src="1.png" alt="" title="" />
</div>
</body>
</html>
ya solo deberias de adaptarlo a los div que quieras.
saludos