title: Export plot in .png with transparent background
body: <p>I am trying to export a simple plot in <em>.png</em> with transparent background. I am able to export it, but the background stays white.</p>
  
  <p><strong>Mock example</strong></p>
  
  <pre><code>x = c(1, 2, 3)
  </code></pre>
  
  <p><strong>I've tried this</strong></p>
  
  <pre><code>plot (x)
  
  dev.copy (png,'myplot.png', bg = 'transparent')
  dev.off()
  </code></pre>
  
  <p><strong>And this</strong></p>
  
  <pre><code>plot (x, bg = 'transparent')
  
  dev.copy (png,'myplot.png')
  dev.off()
  </code></pre>
  
  <p>But neither work. </p>
  
  <p>Can someone help?</p>