title: How does Google's image color search work?
body: <p>Let's say I query for </p>
  
  <blockquote>
    <p><a href="http://images.google.com.sg/images?q=sky&amp;imgcolor=black" rel="nofollow noreferrer">http://images.google.com.sg/images?q=sky&amp;imgcolor=black</a></p>
  </blockquote>
  
  <p>and I get all the black color sky, how actually does the algorithm behind work?</p>