title: Are multiple domain can improve images loading speed
body: <p>I read this article <a href="http://www.websiteoptimization.com/speed/tweak/parallel/" rel="nofollow noreferrer">Optimize Parallel Downloads to Minimize Object Overhead</a> and write a test demo
  But the result is not I expected，look at the waterfall figure multiple domain's images indeed parallel download but the total time no less.</p>
  
  <p>Who can tell me why,thanks</p>
  
  <p><strong>multiple domain image download</strong></p>
  
  <p><img src="https://i.stack.imgur.com/QMGmh.png" alt="multiple domain"></p>
  
  <p><strong>single domain image download</strong></p>
  
  <p><img src="https://i.stack.imgur.com/eemah.png" alt="single domain"></p>