title: can not render images in ipynb files on vscode
body: <p>i have installed vscode with official microsoft python package , every thing is ok except images rendering in markdown </p>
  
  <p>i tried the following codes for displaying images in markdown cell : </p>
  
  <p><code>&lt;img src="images/grad_summary.png" style="width:600px;height:300px;"&gt;</code></p>
  
  <p>alt</p>
  
  <p><code>![title](images/grad_summary.png)</code></p>
  
  <p>but it is not working although it is working on jupyter notebook </p>
  
  <p>P.S.</p>
  
  <p>vscode version:  1.40.1</p>
  
  <p>python version : 3.7</p>
  
  <p>vscode python extension version : 2019.10.44104</p>
  
  <p>os : windows 10</p>
  
  <p>Any Help :)</p>