title: How can I load images one after another?
body: <p>I have a website with a lot of images in it. I want some images load before another (because user will scroll to the last images). Let's say this is html:</p>
  
  <pre><code>&lt;img src='img1.jpg'&gt;
  &lt;img src='img2.jpg'&gt;
  &lt;img src='img3.jpg'&gt;
  &lt;img src='img4.jpg'&gt;
  </code></pre>
  
  <p>How can I make <code>img3.jpg</code> and <code>img4.jpg</code> start to load after <code>img1.jpg</code> and <code>img2.jpg</code> loaded?</p>