Images and Figures

Images

MyST Markdown provides a few different syntaxes for including images in your documentation, as explained below.

The first is the standard Markdown syntax:

![fishy](../images/fun-fish.png)

fishy

This will correctly copy the image to the build folder and will render it in all output formats (HTML, TeX, etc). However, it is limited in the configuration that can be applied, for example setting a width.

As discussed in this section, MyST allows for directives to be used such as image and figure (see the sphinx documentation for available options):

```{image} ../images/fun-fish.png
:alt: fishy
:class: bg-primary
:width: 200px
:align: center
```
fishy

This allows you to control aspects of the image with directive arguments.

In one way, this is an improvement on the Markdown syntax, however, the drawback is that this syntax will not show the image in common Markdown viewers (for example when the files are viewed on GitHub). The final option then is directly using HTML, which can also be parsed by MyST Markdown. Using raw HTML is usually a bad choice (see this explanation), but enabling extended syntax in your _config enables MySt-Parser to properly handle isolated img tags:

parse:
  myst_extended_syntax: true

Now you can add:

<img src="../images/fun-fish.png" alt="fishy" class="bg-primary" width="200px">

and we correctly render:

fishy

This will also be output in PDF LaTeX builds!

Allowed attributes are equivalent to the image directive: src, alt, class, width and height. Any other attributes will be dropped.

Supported image formats

Standard rasterized image formats, such as .png, jpg, are supported for both HTML and LaTeX/PDF output formats. Vector formats, such as .svg, .pdf and .eps, by contrast are normally builder specific. See the supported_image_types specification for each sphinx builder here.

To support multiple builders, Jupyter Book allows you to use a * asterisk as the extension:

<img src="../images/fun-fish.*" alt="fishy" class="bg-primary mb-1" width="200px">

All images matching the provided pattern will then be searched for and each builder chooses the best image out of these candidates.

fishy

You can use a tool such as imagemagick, to pre-convert your images into multiple formats.

Alternatively, you may wish to check out these sphinx extensions:

Figures

MyST Markdown also lets you include figures in your page. Figures are like images, except that they are easier to reference elsewhere in your book, and they include things like captions. To include a figure, use this pattern:

```{figure} ../images/C-3PO_droid.png
---
height: 150px
name: directive-fig
---
Here is my figure caption!
```
../_images/C-3PO_droid.png

Fig. 3 Here is my figure caption!

Note

You can also include figures that were generated from your code in notebooks. To do so, see Insert code outputs into page content.

Markdown Figures

Markdown figures combine colon style admonitions and HTML image parsing, to produce a “Markdown friendly” syntax for figures, with equivalent behaviour to the figure directive above.

To enable them, add in your _config.yml:

parse:
  myst_extended_syntax: true

The figure block must contain only two components; an image, in either Markdown or HTML syntax, and a single paragraph for the caption.

As with admonitions, the figure can have additional classes set on it, but the title is now taken as the reference target of the figure:

:::{figure,myclass} markdown-fig
<img src="../images/fun-fish.png" alt="fishy" class="bg-primary mb-1" width="200px">

This is a caption in **Markdown**!
:::
fishy

Fig. 4 This is a caption in Markdown!

As we see here, the target we set can be referenced:

[Go to the fish!](markdown-fig)

Go to the fish!

Referencing figures

You can then refer to your figures using the {ref} role or Markdown style references like:

- {ref}`directive-fig`
- [](markdown-fig)

which will replace the reference with the figure caption like so:

Numbered references

Another convenient way to create cross-references is with the {numref} role, which automatically numbers the labelled objects. For example, {numref}`directive-fig` will produce a reference like: Fig. 3.

If an explicit text is provided, this caption will serve as the title of the reference.

- {ref}`Fly to the droid <directive-fig>`
- [Swim to the fish](markdown-fig)

With numref, you can also access the figure number and caption individually: the characters “%s” and “{number}” will be replaced with a figure number, while “{name}” will be replaced with a figure caption.

For example, {numref}`Figure {number}: {name} <directive-fig>` will produce: Figure 3: Here is my figure caption!.

Margin captions and figures

You can include a figure caption on the margin using :figclass: margin-caption as seen in Fig. 5.

../_images/cool.jpg

Fig. 5 Here is my figure caption!

Another option is to include figures on the margin using :figclass: margin as seen in Fig. 6.

../_images/cool.jpg

Fig. 6 Here is my figure caption!

Figure scaling and alignment

Figures can also be aligned by using the option :align: right or :align: left. By default, figures are aligned to the center (see Fig. 3).

```{figure} ../images/cool.jpg
---
scale: 50%
align: left
---
Here is my figure caption!
```
../_images/cool.jpg

Fig. 7 Here is my figure caption!

```{figure} ../images/cool.jpg
---
scale: 50%
align: right
---
Here is my figure caption!
```
../_images/cool.jpg

Fig. 8 Here is my figure caption!

Figure Parameters

The following options are supported:

scale : integer percentage

Uniformly scale the figure. The default is “100” which indicates no scaling. The symbol “%” is optional.

width : length or percentage

You can set the figure width in the following units: “em”, “ex”, “px”,”in” ,”cm”, “mm”, “pt”, “pc”, “%”.

height : length

You can set the figure height in the following units: “em”, “ex”, “px”, “in”, “cm”, “mm”, “pt”, “pc”, “”.

alt : text

Text to be displayed if the figure cannot display, or if the reader is using assistive technologies. Generally entails a short description of the figure.

align : “left”, “center”, or “right”

Align the figure left, center, or right. Default alignment is center.

name : text

A unique identifier for your figure that you can use to reference it with {ref} or {numref}. Cannot contain spaces or special characters.

figclass : text

Value of the figure’s class attribute which can be used to add custom CSS or JavaScript. Predefined options include:

  • “margin” : Display figure on the margin

  • “margin-caption” : Display figure caption on the margin