title: Detect "overall average" color of the picture
body: <p>I have a jpg image.</p>
  
  <p>I need to know "overall average" the color of the image. At first glance there can use the histogram of the image (channel RGB).</p>
  
  <p>At work I use mostly JavaScript and PHP (a little Python) therefore welcomed the decision in these languages. Maybe ther are library for working with images that address similar problems.</p>
  
  <p>I do not need to dynamically determine the color of the picture. I need just once go through the entire array of images and determine the color of each separately (this information I will remember for future use).</p>