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#### 12.7.5 Images in DocBook export

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.