title: With Bokeh, how to save to a png or jpg instead of a html file?
body: <p>I need to export pictures of the graphs and plots I am creating with Bokeh.</p>
  
  <p>Usually I do</p>
  
  <pre><code>output_file("test.html")
  </code></pre>
  
  <p>However, I want to copy that graph into an Excel Sheet.
  It does not have to be interactive anymore, though that would be brillant.
  How do I export the graph as a picture? Using code, not clicking on "preview/save".</p>