Works for me with
Code:
ebook-convert Image.docx oeb --docx-no-cover && cat oeb/index.html
<?xml version='1.0' encoding='utf-8'?>
<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
<head>
<title>Unknown</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<link href="stylesheet.css" rel="stylesheet" type="text/css"/>
<link href="page_styles.css" rel="stylesheet" type="text/css"/>
</head>
<body class="calibre">
<p lang="de" class="block_">Image attribute test</p>
<p class="block_"><img src="images/Calibre_logo_2.png" title="This is the image title." alt="This is the image description." class="calibre1"/></p>
</body></html>