I've ever used this code to add an "ex libris" into my books.
Code:
<?xml version='1.0' encoding='utf-8'?>
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<title>Ex libris</title>
</head>
<body>
<div>
<table width="100%" height="100%" valign="center">
<tr>
<td align="center">
<img src="../images/logo.png" width="44%"/>
</td>
</tr>
</table>
</div>
</body>
</html>
up until the version 2.41 the image "src="../images/logo.png" was correctly showed in the center (horizontal and vertical center) of the preview panel. With version 2.42 the image is showed in the upper side of the pane.
If you try to change the <table ...> tag in the upper code with this one
Code:
<table width="100%" height="100%" valign="center" border="1px">
You can see better how bad is rendered the table.