Hugo has figure shortcode built-in, so you can easily add figure captions or hyperlink rel attributes to images. Documentations can be found here:
https://gohugo.io/content-management/shortcodes/#figure
This theme has 3 CSS classes made for figure elements:
big: images will break the width limit of main content area. left: images will float to the left. right: images will float to the right. If a figure has no class set, the image will behave just like a normal markdown image: !
