I forgot to close the <p> in the code example. Corrected version:

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
</head>
<body>
<p><img src="" alt="" /></p>
<body>
</html>