Usually, I would chop that image up into 3 rectangular ones - the header, the body and the email part.
Since it's not like that I've just used the trick used for the email field, explicitly setting divs to cover the header and body (of the image) I've then set the links within these elements to fill them - effectively giving you a div with a href.
As I started typing this, I remembered about image-maps - perhaps they would be a better implementation?
Anyway, I've just replaced everything below your </script>
tag. It's fine with IE8 and current Chrome.
<style>
/* set the image as a background-image of a div */
div #splash-image
{
background-image: url('Thuisverpleging Eric Jacobs_files/splash_image2.png');
width: 1057px;
height: 863px;
}
/* resposition it */
#clickable-email
{
left: 216px;
}
#greyHeader a, #blueMain a
{
display: block;
}
#greyHeader
{
position: absolute;
left: 539px;
top: 20px;
width: 596px;
height: 90px;
}
#greyHeader a{ height: 90px; }
#blueMain
{
position: absolute;
left: 216px;
top: 110px;
width: 916px;
height: 580px;
}
#blueMain a{ height: 580px; }
</style>
</head>
<!--
Usage of certain elements
-----------------------------
class:
- center en width-x-px moeten samen voorkomen om te werken in alle browsers
- height-x moet voorkomen op een div
-
-->
<body class="wpc hpc no-padding-margin center-ie splash">
<!-- Content of the site -->
<div id="splash-content">
<div id="splash-image" class="center">
<a href="http://www.thuisverplegingjacobs.be/site/index.php"></a>
</div>
</div>
<div id='greyHeader'>
<a href="http://www.thuisverplegingjacobs.be/site/index.php"> </a>
</div>
<div id='blueMain'>
<a href="http://www.thuisverplegingjacobs.be/site/index.php"> </a>
</div>
<div id="clickable-email">
<a href="mailto:info@thuisverplegingjacobs.be"> </a>
</div>
</body>
</html>