title: Chunky PNG Image comparison- How to highlight multiple Differences
body: <p>I've just discovered <a href="http://jeffkreeftmeijer.com/2011/comparing-images-and-creating-image-diffs/" rel="nofollow noreferrer">this article</a>, which talks about comparing two images in Ruby and highlighting the differences.</p>
  
  <p>But if I have images with multiple differences, e.g.: one difference is in the header and the other in the footer it will draw a rectangle on whole image.</p>
  
  <p>Is it possible to draw a separate rectangle on each and every difference?</p>