Images that are
linked to without a description part in the link, like
‘[[file:img.jpg]]’ or
‘[[./img.jpg]]’, will be exported to
DocBook using mediaobject elements. Each
mediaobject element contains an
imageobject that wraps an imagedata
element. If you have specified a caption for an image as
described in Images and tables,
a caption element will be added in
mediaobject. If a label is also specified, it will
be exported as an xml:id attribute of the
mediaobject element.
Image attributes supported by the imagedata
element, like align or width, can be
specified in two ways: you can either customize variable
org-export-docbook-default-image-attributes or use
the #+ATTR_DOCBOOK: line. Attributes specified in
variable org-export-docbook-default-image-attributes
are applied to all inline images in the Org file to be exported
(unless they are overridden by image attributes specified in
#+ATTR_DOCBOOK: lines).
The #+ATTR_DOCBOOK: line can be used to specify
additional image attributes or override default image attributes
for individual images. If the same attribute appears in both the
#+ATTR_DOCBOOK: line and variable
org-export-docbook-default-image-attributes, the
former takes precedence. Here is an example about how image
attributes can be set:
#+CAPTION: The logo of Org-mode
#+LABEL: unicorn-svg
#+ATTR_DOCBOOK: scalefit="1" width="100%" depth="100%"
[[./img/org-mode-unicorn.svg]]
By default, DocBook exporter recognizes the following image
file types: jpeg,
jpg, png, gif, and svg. You can customize variable
org-export-docbook-inline-image-extensions to add
more types to this list as long as DocBook supports them.