title: Specify image size in GitHub markdown using ems (or other unit)
body: <p>I've seen that it's possible to <a href="https://stackoverflow.com/questions/24383700/resize-image-in-the-wiki-of-github-using-markdown">specify the image size using pixels</a>, but pixels isn't a great way to specify image size. I've tried</p>
  
  <pre><code>&lt;img src="myimg.png" style="width:20em" /&gt;
  </code></pre>
  
  <p>but that didn't work (although <a href="https://chrome.google.com/webstore/detail/markdown-viewer/ckkdlimhmcjmikdlpkmbgfkaikojcbjk" rel="nofollow noreferrer">Markdown Viewer for Chrome</a> rendered it)</p>
  
  <p>Is it even possible to specify the size with another size unit other than pixels? </p>