title: how to place image in material ui button by passing startIcon prop
body: <p>I am using Material ui Button. this button should hold an image &amp; button-name as its child. i don't want to use  as one of the children of my Button, but i want to do it by passing startIcon prop to Button. button should look like:-</p>
  
  <p>i have tried this:-</p>
  
  <pre><code>&lt;Button className={classes.navButtons} startIcon={ZapierIcon}&gt;
      Zapier
  &lt;/Button&gt;
  </code></pre>
  
  <p>but it is showing path of my image in button instead of actual image....can anyone give some suggestion what i am doing wrong.</p>