Image does not appear centered in KOReader but appears centered in Calibre renderer

ilikelilies · 01-09-2026, 12:54 PM

Good Afternoon,

I would like help formating an epub. I am not new to KOReader, but I _am_ new to manually formatting epubs with Calibre. Before I used to just use all epubs regardless of whether they were appropriately formatted, but lately I wanted to try getting some experience formatting them for them to look better.

The main issue I have encountered for now is with a certain epub where an image appears centered in the Calibre renderer but not in KOReader. KOReader, if I remember correctly, uses crengine, and I assume the Calibre renderer must use something based on WebKit or something similar, so that explains the difference. However, I have yet to find a solution.

The HTML body of the page concerned is below:

Code:

<body class="calibre1">
<h2 class="part-number"><em>Zero</em></h2>
<p class="centered-image-1"><img alt="Separator Image Missing" height="1" src="../images/line.jpg" width="84"/></p>
<h2 class="part-title">7 August 1944</h2>
</body></html>

The `centered-image-1` class is as follows:

Code:

p.centered-image-1 {
  text-align: center !important;
  text-indent: 0;
  margin-top: 0;
  margin-bottom: 1em;
}

`img1.png` is a screenshot of the Calibre renderer's output.

`img2.png` is a screenshot of KOReader's rendering.

The image is the line after the header "Zero".

I have yet to find a way to make the image properly center in KOReader.

<br>
<br>
<br>

Bonus question 1: Why do the same images, in different epub files but inserted with the same class, scale differently? In one epub, a width of `256` was sufficient, whereas with the other I had to change that to `512`. This difference is only present in KOReader, Calibre shows them at equal sizes when both are set to `256`.

Bonus question 2: I have a publisher information page that gets rendered properly (with text centering) with Calibre but not with KOReader. `img3.png` is how it looks rendered by Calibre, `img4.png` is how it looks in KOReader. How can I make it look like on Calibre in KOReader?

I know this is a lot so thank you very much for your time :)

Frenzie · Today, 03:27 PM

The test case as given doesn't render as in the screenshot. There's either another style in the book or a style tweak like left align most text is active (or perhaps embedded styles are disabled). Please provide a complete minimal testcase if it's not one of the latter two.

01-09-2026, 12:54 PM	#1
ilikelilies Junior Member Posts: 1 Karma: 10 Join Date: Jan 2026 Device: Kobo Libra 2	Image does not appear centered in KOReader but appears centered in Calibre renderer Good Afternoon, I would like help formating an epub. I am not new to KOReader, but I _am_ new to manually formatting epubs with Calibre. Before I used to just use all epubs regardless of whether they were appropriately formatted, but lately I wanted to try getting some experience formatting them for them to look better. The main issue I have encountered for now is with a certain epub where an image appears centered in the Calibre renderer but not in KOReader. KOReader, if I remember correctly, uses crengine, and I assume the Calibre renderer must use something based on WebKit or something similar, so that explains the difference. However, I have yet to find a solution. The HTML body of the page concerned is below: Code: <body class="calibre1"> <h2 class="part-number"><em>Zero</em></h2> <p class="centered-image-1"><img alt="Separator Image Missing" height="1" src="../images/line.jpg" width="84"/></p> <h2 class="part-title">7 August 1944</h2> </body></html> The `centered-image-1` class is as follows: Code: p.centered-image-1 { text-align: center !important; text-indent: 0; margin-top: 0; margin-bottom: 1em; } `img1.png` is a screenshot of the Calibre renderer's output. `img2.png` is a screenshot of KOReader's rendering. The image is the line after the header "Zero". I have yet to find a way to make the image properly center in KOReader. <br> <br> <br> Bonus question 1: Why do the same images, in different epub files but inserted with the same class, scale differently? In one epub, a width of `256` was sufficient, whereas with the other I had to change that to `512`. This difference is only present in KOReader, Calibre shows them at equal sizes when both are set to `256`. Bonus question 2: I have a publisher information page that gets rendered properly (with text centering) with Calibre but not with KOReader. `img3.png` is how it looks rendered by Calibre, `img4.png` is how it looks in KOReader. How can I make it look like on Calibre in KOReader? I know this is a lot so thank you very much for your time :) Attached Thumbnails Last edited by ilikelilies; 01-09-2026 at 12:56 PM.

Today, 03:27 PM	#2
Frenzie Wizard Posts: 1,795 Karma: 731691 Join Date: Oct 2014 Location: Antwerp Device: Kobo Aura H2O	The test case as given doesn't render as in the screenshot. There's either another style in the book or a style tweak like left align most text is active (or perhaps embedded styles are disabled). Please provide a complete minimal testcase if it's not one of the latter two. Attached Thumbnails

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