images-and-xhtml-export.org

Images and XHTML export

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Image basics

Images are inserted into an Org file in a fashion similar to links:

[[file:/img/org-mode-unicorn.png]]

The file: prefix is optional, as long as a known image type is used. Org-mode recognizes images by the file name suffix. Recognized suffixes are all the members of org-export-html-inline-image-extensions which defaults to the list ("png" "jpeg" "jpg" "gif"). That said, the images above could as well be included using this link:

[[/img/org-mode-unicorn.png]]

The special form

 [[/img/org-mode-unicorn.png][Monocerus glaucus]]

exports to a link to the image:

<a href="/img/org-mode-unicorn.png">Monocerus glaucus</a>

For this tutorial, we assume the variable org-export-html-inline-images is unchanged from its standard setting, i.e. maybe. Images are shown in the exported page this way. And we will talk about visible images only.

Don’t be afraid. Most of the text in this little tutorial is just blind text (and in gray color therefor).

Read the basics about images in XHTML export in the Org-mode manual, Section Images (e.g. show a thumbnail, that links to a high resolution image…).

A simple image

Let’s simply put an image inside a paragraph like this

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh
[[[[/img/org-mode-unicorn.png]]]]
euismod  tincidunt ut laoreet dolore magna aliquam erat volutpat.

Note, that empty lines are crucial. The exporter will start a new paragraph, if you add an empty line before or after the image. You can easily try that yourself, simply by adding an empty line before and/or after the image and export again.

To see the result, export your Org file to HTML (press C-x C-e b) and see the results. Note, that the image is displayed just where you placed it.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

@html:</span>@@

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

@html:</span>@@

Image attributes

Org-mode allows us to add HTML attributes to the exported image. There are several useful attributes, some of which are mandatory, as the src and alt attributes. Org-mode adds an empty alt attribute for you, if not supplied. You can add additional attributes using a special syntax. E.g. you could change the value of the alt attribute this way:

#+ATTR_HTML: :alt My fancy value for the alt attribute
[[/img/org-mode-unicorn.png]]

You may add more attributes to an #+ATTR_HTML: line. More than one #+ATTR_HTML: line is allowed for readability. Example:

#+ATTR_HTML: :alt Zoomed image.
#+ATTR_HTML: :width 300 :style border:2px solid black;
[[/img/org-mode-unicorn.png]]

A full list of valid attributes can be found on http://www.w3schools.com/tags/tag_img.asp.

Align images

If you want text to flow around your images, the style attribute comes handy. To place the image on the left, and let the text flow around the image on the right, use this code:

#+ATTR_HTML: :style float:left;

Possible values for the float: CSS attribute are left, right and none (the default). left causes the image to show up on the left of the text succeeding the image, right will place the image on the right side of the text succeeding the image.

You can control the gap between image and surrounding text, using the margin: CSS attribute like so:

#+ATTR_HTML: :style float:left;margin:20px 20px 20px 0px;

The order of the values given, are the distances in the north east south, and west.

Again: Please avoid empty lines before and after the image, if you want to achieve the effect shown in this example: one paragraph of text that flows around two images. The exporter adds a <p> element for empty lines otherwise.

This code shows, how we can add attributes to the <img ... /> tag in Org-mode:

#+ATTR_HTML: :style float:right;margin:0px 0px 20px 20px;
[[/img/org-mode-unicorn.png]]
Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy
#+ATTR_HTML: :style float:left;margin:20px 20px 20px 0px;
[[/img/org-mode-unicorn.png]]
euismod  tincidunt ut laoreet dolore magna aliquam erat volutpat.

Note: The #+ATTR_HTML: line as well as the image definition have to be on a single line respectively. Don’t put any additional text on those lines or the attributes will not be added to the image tag on export!

This text is directly succeeds the first image, which is right aligned. Because of the alignment, placing the image after the first few lines would make no difference.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.

@html:</span>@@

Text before the second image ends here.

This text is directly following the second image. No empty lines are added. Neither before, nor after the image. We therefor see one big paragraph with two images. Note, that browsers will place this second image where ever they see fit. Browsers will not interrupt the text flow, just to place the image add the exact point between two words.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.

@html:</span>@@

Images in a row

And here is how to fill the width of your display with images and let the lines break automatically. Just add display:inline; to the style attributes.

#+ATTR_HTML: :style display:inline;margin:10px;
[[/img/org-mode-unicorn.png]]
#+ATTR_HTML: :style display:inline;margin:10px;
[[/img/org-mode-unicorn.png]]
#+ATTR_HTML: :style display:inline;margin:10px;
[[/img/org-mode-unicorn.png]]
#+ATTR_HTML: :style display:inline;margin:10px;
[[/img/org-mode-unicorn.png]]

results in:

Images with Captions

You might want to attach a caption to your images. You can do so using this code:

#+CAPTION: Monocerus glaucus
#+ATTR_HTML: :alt Monocerus glaucus
[[[[/img/org-mode-unicorn.png]]]]

In this case, empty lines before and after the image make no difference since the exporter ends paragraphs and restarts them below the image.

{{{BeginBlindText }}}Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. @html:</span>@@

Captions and floating

There is no figure element in XHTML and captions are not supported at all. But the exporter wraps the <img..../> tag in certain containers to add the caption for you:

<div class="figure">
<p><img src="path/to/img.png" alt="Monocerus glaucus" /></p>
<p>Monocerus glaucus</p>
</div>

To make text flow around your image, you need to adjust the styles for the special HTML elements that wrap images with captions. The exporter puts the default styles in the <head> section of your XHTML files. This is, what they look like:

div.figure { padding: 0.5em; }
div.figure p { text-align: center; }

To achive the floating, add this to the top of the Org-file:

#+STYLE: <style type="text/css">
#+STYLE:<!--/*--><![CDATA[/*><!--*/
#+STYLE: div.figure { float:left; }
#+STYLE: /*]]>*/-->
#+STYLE: </style>

The crucial attribute is float:left;. Choose float:right; to place the images on the right edge of your paragraphs. The styles will apply to all images with captions in your file.

Note (again): In this case, empty lines before and after the image make no difference since the exporter ends paragraphs and restarts them below the image. This said, a floating image with a caption will always sit on the top left/right of the following paragraph.

Result:

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.

@html:</span>@@

This text directly preceeds the image and ends here.

This text directly follows the image. No empty are inserted before or after the image. Note, that a new paragraph has started nonetheless.

{{{BeginBlindText }}}

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo…

@html:</span>@@

Problems with captions and float

The float:left; style causes following blocks to show up on the right of your image. So did the following paragraph in the previous example. Inevitably, this will happen against your will. In that case, put this after the image:

#+begin_export html
 <br style="clear:both;" />
#+end_export

Or you could use the less obtrusive syntax:

@<br style="clear:both;" />

Captions in a row

In addition, float:left; changes the alignment of several images with caption in a row. They now fill a row on the display, until the screen width is filled with images. They now behave like simple text.

#+CAPTION: Michael
#+ATTR_HTML::alt image
[[/img/org-mode-unicorn.png]]
#+CAPTION: Steve
#+ATTR_HTML::alt image
[[/img/org-mode-unicorn.png]]
#+CAPTION: Carla
#+ATTR_HTML::alt image
[[/img/org-mode-unicorn.png]]
#+CAPTION: Pete
#+ATTR_HTML::alt image
[[/img/org-mode-unicorn.png]]

... etc. - many more ...

results in:

Italic captions

Captions are often printed in italics. To do so, go to the top of your Org-file again, and edit the styles again:

#+STYLE: <style type="text/css">
#+STYLE:<!--/*--><![CDATA[/*><!--*/
#+STYLE: div.figure p { font-style:italic; }
#+STYLE: /*]]>*/-->
#+STYLE: </style>

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.

@html:</span>@@

Final captions example

Here is a last weird example of what styles can do for you. Let’s put the caption to the right of an image.

#+STYLE: <style type="text/css">
#+STYLE:<!--/*--><![CDATA[/*><!--*/
#+STYLE: div.figure {
#+STYLE:  width:235px; /* ensure the same width for each. */
#+STYLE:  float:left;
#+STYLE:  margin:5px;
#+STYLE: }
#+STYLE: div.figure p {
#+STYLE:  display:inline;
#+STYLE:  font-style:italic;
#+STYLE: }
#+STYLE: /*]]>*/-->
#+STYLE: </style>

If the sum of three div.figure’s widths and margins were so wide, that three Monoceri wouldn’t fit in one row, this text would start on the very top of this mini page.

Let’s add another little paragraph here, to show how float works. How to get out of here?

=@<br style="clear:both;"/>=

…did the trick. It’s advisable, to add this after the third image above since the first paragraph starts with very short words.

Summary

1. Images are referenced using Org-mode’s link syntax.
2. As for simple links, the file: prefix is optional, as long as the suffix is a member of org-export-html-inline-image-extensions.
3. We can add HTML attributes to images
   • using #+ATTR_HTML:
   • Both, the #+ATTR_HTML: line and the image have to be on their own line.
4. We prefer the style attribute to align images. The most important CSS attributes are float: and margin:.
5. We can add a caption to images, even though (X)HTML doesn’t support this. We use the special #+CAPTION: line to supply a caption. This has to be on a single line, too.
6. The exporter wraps the image and the caption into a <div class=”figure"> and two <p> elements. The first <p> element contains our image, the second one the caption.
7. By adding special styles for those elements to the top of our Org-file (#+STYLE:), we can align images with captions, too.
8. Styles added for images with captions apply to all images with captions in the file.