<script>          
  (function () {
    var d = document, s = d.createElement('script');
    s.src = 'https://www.kurtli.com/feed/embed.js';
    s.setAttribute('data-timestamp', +new Date());
    (d.head || d.body).appendChild(s);
  })();
</script>

And it will look like this:

How does it work?

The JavaScript code will load your images from Slack and display them on your website. As soon as you upload a new image, it will be displayed.