title: Z-index transparent image
body: <p>I need to take an existing banner image that has, as part of the image, a company logo at the left hand side of the image, but the whole banner is an image.</p>
  
  <p>Now what I am after, is a means of creating a layer region (transparent/invisible) over the existing image logo, so that:</p>
  
  <ol>
  <li>the original image can still be seen &amp;</li>
  <li>when you hover over the layered region covering the logo underneath, I want to hyperlink this to a specified URL</li>
  </ol>
  
  <p>I have thought about z-index but unsure how to use this and especially how to calculate the exact dimensions of my new layered image.</p>
  
  <p>Is there a tool that will calculate the four points required to overlap over logo?</p>