title: Saving html file with images in bokeh
body: <p>I'm creating a bokeh plot containing several images. 
  I create and show my file like this:</p>
  
  <pre><code>output_file(my_dir + "Graphs\\graph")
  show(bar)
  </code></pre>
  
  <p>It then shows me the plot and creates a graph.html file in my directory "Graphs". But when I open the html later, the plot doesn't contain the images.
  How can I save the html file, so that it contains the images as well?</p>