title: Image saved con Amazon S3 bucket not showing on HTML5 canvas. Crossorigin issue
body: <p>I have an image saved on my AWS S3 bucket. This is my CORS configuration:</p>
  
  <pre><code>&lt;CORSConfiguration&gt;
      &lt;CORSRule&gt;
          &lt;AllowedOrigin&gt;*&lt;/AllowedOrigin&gt;
          &lt;AllowedMethod&gt;GET&lt;/AllowedMethod&gt;
          &lt;MaxAgeSeconds&gt;3000&lt;/MaxAgeSeconds&gt;
          &lt;AllowedHeader&gt;Authorization&lt;/AllowedHeader&gt;
      &lt;/CORSRule&gt;
  &lt;/CORSConfiguration&gt;
  </code></pre>
  
  <p>Also, the bucket has this policy:</p>
  
  <pre><code>{
      "Version": "2012-10-17",
      "Id": "Policy1468082822770",
      "Statement": [
          {
              "Sid": "Stmt1468082812651",
              "Effect": "Allow",
              "Principal": "*",
              "Action": "s3:GetObject",
              "Resource": "arn:aws:s3:::criptolibertad/*"
          }
      ]
  }
  </code></pre>
  
  <p>This is the image: <a href="https://criptolibertad.s3.amazonaws.com/Django/0_startproject.jpeg" rel="nofollow">https://criptolibertad.s3.amazonaws.com/Django/0_startproject.jpeg</a> , as you can see, it is public. I use a library called <a href="https://github.com/Foliotek/Croppie" rel="nofollow">Croppie</a> that tries to load the image into a canvas. But the canvas doesn't show the image I don't know why. The js looks like this:</p>
  
  <pre><code>croppie_div.croppie('bind', {
      url: "{{ carta_magicpy.imagen_base.url }}",
      points:  [10,10,300,600]
  });
  </code></pre>
  
  <p>That <code>url</code> attribute is just a variable rendered by Django. It looks like this when it is rendered:</p>
  
  <pre><code>&lt;img style="opacity: 0;" src="https://criptolibertad.s3.amazonaws.com/Django/0_startproject.jpeg" crossorigin="anonymous" class="cr-image"&gt;
  </code></pre>
  
  <p>Notice the <code>crossorigin</code> attribute. I went into Croppie's source and removed that attribute. But then I get the error:</p>
  
  <blockquote>
    <p>Image from origin ... has been blocked from loading by Cross-Origin Resource Sharing policy:
    No 'Access-Control-Allow-Origin' header is present on the requested
    resource</p>
  </blockquote>
  
  <p>How can I solve this?</p>