Ensure images show up in both JupyterLab and rendered on website

[scottyhq]

Figure directives are great for generating labels and having things look nice on the website:

```{figure} ../../img/sentinel1_radar_vision.jpg
---
height: 400px
name: sentinel1
---
Artist view of Sentinel-1. [Source](https://www.esa.int/ESA_Multimedia/Images/2014/01/Sentinel-1_radar_vision)

https://snowex-hackweek.github.io/website/tutorials/sar/sentinel1.html

But when actually running the notebook in a jupyterlab environment the figure is not rendered and just restates the directive:

---
height: 400px
name: sentinel1
---
Artist view of Sentinel-1. [Source](https://www.esa.int/ESA_Multimedia/Images/2014/01/Sentinel-1_radar_vision)

Seems the best solution is to use HTML tags as described here https://jupyterbook.org/content/figures.html#raw-html-images cc @mikedurand