A little SVG works well for me:
PHP Code:
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:svg="http://www.w3.org/2000/svg">
<head>
<title>Cover</title>
<link rel="stylesheet" type="text/css" href="nookstyles.css" />
<link rel="stylesheet" type="text/css" href="nookstyles2.css" />
<style type="text/css">
html,body {
height: 100% !important;
min-height: 100% !important;
width: 100% !important;
margin: 0 !important;
border-width: 0 !important;
padding: 0 !important;
}
div.coverpage {
height: 100%;
margin: 0;
padding: 0;
border-width: 0;
}
</style>
</head>
<body style="oeb-column-number: 1; background-color: #000000;" >
<div class="coverpage">
<svg
xmlns:svg="http://www.w3.org/2000/svg"
xmlns="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink"
version="1.1"
width="100%"
height="100%"
id="svg2"
xml:space="preserve" viewBox="0 0 2040 2640" preserveAspectRatio="xMidYMid">
<image xlink:href="efw-frontcover.jpg" height="2640" width="2040">
<desc>Patriots: Enemies From Within</desc>
</image>
</svg>
</div>
</body>
</html>
This content works for me in ADE-based readers, Kindle (with the addition of wrapper divs so non-KF8 readers see only the image), Nook, and iBooks. Note that the values 2040 and 2640 must both be replaced in two places by the actual dimensions of the image itself.