View Full Version : Cover art thumbnails?

08-04-2010, 12:11 PM
Sorry if this question has been covered before. I tried searching but ...... maybe I just didn't use the correct search terms/phrases. I am trying to get cover art to show up as a thumbnail on the bookshelf of reader programs such as Aldiko but not having any luck.

I download a txt file from Gutenberg, edit out the extra stuff, then convert it to epub with Calibre. I add the cover art in Calibre but apparently that image is only used by Calibre ... it doesn't transfer to my reader. I will load the book into my reader, open Aldiko, and the book is shown on the bookshelf but without any cover art image, just text. The Calibre "cover_image.jpg" does show up on the first page of the book and I have replaced that with the image I want successfully. The image appears on the books first page fine ... but still not as a thumbnail on the bookshelf. (actually what I do is delete the Calibre "cover_image.jpg" and add/rename the image I want)

What do I need to change or add to get a thumbnail for the bookshelf? When I unzip the Calibre epub I find two (2) html files:

<?xml version='1.0' encoding='utf-8'?>
<html xmlns="" xml:lang="en">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
<meta name="calibre:cover" content="true"/>
<style type="text/css" title="override_css">
@page {padding: 0pt; margin:0pt}
body { text-align: center; padding:0pt; margin: 0pt; }
<svg xmlns="" xmlns:xlink="" version="1.1" width="100%" height="100%" viewBox="0 0 600 800" preserveAspectRatio="none">
<image width="600" height="800" xlink:href="cover_image.jpg"/>

<?xml version='1.0' encoding='utf-8'?>
<html xmlns="">
<meta content="; charset=utf-8" http-equiv="Content-Type"/><link href="stylesheet.css" type="text/css" rel="stylesheet"/><style type="text/css">
@page { margin-bottom: 5.000000pt; margin-top: 5.000000pt; }</style></head>
<body class="calibre">
<p class="calibre1">EVE'S DIARY</p>
<p class="calibre1">By Mark Twain</p>
<p class="calibre1">Translated from the Original</p>
<p class="calibre1">SATURDAY.--I am almost a whole day old, now. I arrived yesterday. That is as it seems to me. And it must be so, for if there was a day-before-yesterday I was not there when it happened, or I should remember it. It could be, of course, that it did happen, ...............goes on to the complete text of book ........................

08-04-2010, 04:31 PM
A little googling ( shows that Aldiko isn't able to render the cover html specified in the guide and resorts to making a guess about the cover image. Epub does have a standard way to specify an html file for the cover, but doesn't specify a simple image file.

08-05-2010, 01:55 PM
What I got from your link is that it's hard to suggest a fix because there are no standards; every reader or software program uses different instructions/alogorithms to generate a thumbnail.

I'll continue to just mess around inside the backup files until I find out what works for what I want/am using.


08-05-2010, 04:11 PM
The 'fix' is for the reader to render the xhtml specified in the guide entry for the cover instead of whining. Obviously Aldiko's algorithm isn't that sophisticated if it can't discover a jpeg named 'cover_image'. iBooks is almost as bad, but at least it uses a metadata entry that is quite easy to insert.

08-05-2010, 04:13 PM
Actually, the correct behavior IMO is to render a "screenfull" of the first item in the spine.

08-05-2010, 05:51 PM
The 'fix' is for the reader to render the xhtml specified in the guide entry for the cover instead of whining.

I guess I'll just go on whining until I learn this stuff. Apparently you were born knowing all of this and were never a newb. P.O.

08-05-2010, 11:11 PM
He didn't mean you, he meant the device.