Looks like you, or someone, tried to add the new cover image multiple times. Try this:
Code:
<body style="margin: 0px; padding: 0px;">
<div style="width: 100%; height: 100%; margin: 0; padding: 0; text-align: center;">
<img alt="Cover" src="../Images/decembercover2.jpg" />
</div>
</body>
and as mrmikel said, be sure that the image "decembercover2.jpg has the semantic "cover image" selected.