title: Set dpi with plotly
body: <p>I know that savefig has an option dpi. but if I make plots with plotly and write image I don't have an option to set dpi. </p>
  
  <p>How can I set dpi with plotly?</p>
  
  <pre><code>TypeError: write_image() got an unexpected keyword argument 'dpi'
  </code></pre>