Why do IE and Firefox render the same image differently, how can I prevent it?

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="ctl00_Head1"><title></title>
</head>
<body>
<img src="http://www.google.com/intl/en_ALL/images/logo.gif" />
</body>
</html>