Slide over picture viewer

Link: http://www.massexod.us/blog/how-to-create-before-and-after-images-for-squarespace

Download css codes and add as files wit link tool

Inject code to site, footer section

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
<script>window.jQuery || document.write('<script src="/s/jquery-213min.js"><\/script>')</script>
<script src="/s/jqueryeventmove.js" type="text/javascript"></script>
<script src="/s/jquerytwentytwenty_mx.js" type="text/javascript"></script>
<link rel="stylesheet" href="/s/twentytwenty.css" type="text/css" media="screen" />

On page or in footer section for site

<script>
$(window).load(function() {
  $(".sqs-gallery-block-stacked").twentytwenty();
});
</script>