title: Light up image on hover
body: <p>Take a look at <a href="http://www.kickstarter.com" rel="noreferrer">http://www.kickstarter.com</a>. </p>
  
  <p>When you hover over their logo, the image lights up. Is this effect doable without using a different image on hover? </p>
  
  <p>My first idea was to use <code>::after:hover</code> and add a white square with high transparency that covers the logo, <strong>but since my logo is placed on a blue background this would not work.</strong> Another idea is to set opacity to 0.9 and on hover set it to 1. But this makes the image look too dark by default.</p>