title: Removing an image from a canvas in HTML5
body: <p>there's an example, which loads 2 images:</p>
  
  <pre><code>    canvas = document.getElementById("canvas");
      ctx = canvas.getContext("2d");
  
      var img1 = new Image();
      img.src = "/path/to/image/img1.png";
      img.onload = function() {
        ctx.drawImage(img, 0, 0);
      };
  
      var img2 = new Image();
      img2.src = "/path/to/image/img2.png";
      img2.onload = function() {
        ctx.drawImage(img2, 100, 100);
      };
  </code></pre>
  
  <p>I need to remove(replace) img2 from canvas. What is the <strong>best</strong> way to do it?</p>