title: How to display images in groups column in vis.js?
body: <p>How to display images in the "groups" column in vis.js, like this?</p>
  
  <p><a href="https://i.stack.imgur.com/38Cum.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/38Cum.jpg" alt="enter image description here"></a></p>