title: Express send base-64 encoded png-image
body: <p>In my node.js app I`m trying to respond with an image.</p>
  
  <p>This image was saved before postgresql as text.</p>
  
  <p>The text looks just like this:</p>
  
  <pre><code>data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAPAAAAE
  </code></pre>
  
  <p><b>But when I try to return it as an image:</b></p>
  
  <pre><code>    res.type('image/png');
      res.send(image_string); 
  </code></pre>
  
  <p>Or binary:</p>
  
  <pre><code>     res.send(image_string,'binary'); 
  </code></pre>
  
  <p>It shows a empty image-element: 
  <a href="https://i.stack.imgur.com/nAqwp.png" rel="noreferrer"><img src="https://i.stack.imgur.com/nAqwp.png" alt="enter image description here"></a></p>
  
  <p><b>What do I wrong?</b>Thanks</p>