test

HTML

<body style='font-size:64px;'>
    <div id="chatBox">

    </div>

    <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.0.0-alpha1/jquery.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
    <script>
      function addChatMessage(msg)
      {
        $('#chatBox').prepend(msg);
      }
    </script>
  </body>

CSS

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">

JavaScript

addChatMessage("<img src='data:image/png;base64,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' width='auto' height='20em'/>");