title: Center image in html button
body: <p>I'm trying to show a simple button, with an image on it, like this:</p>
  
  <pre><code>&lt;button type="button" style="width: 23px; height: 23px; padding:0"&gt;
      &lt;img src="Icon_304.png" /&gt;
  &lt;/button&gt;
  </code></pre>
  
  <p>The button looks right in Chrome, but is off a bit in Firefox—it's not horizontally centered, but skewed to the right.  A FF screenshot is below.  How can I get the image to be centered (like it is in Chrome by default)?  I tried adding a margin: 0 to the img, to no avail.</p>
  
  <p><img src="https://i.stack.imgur.com/rr2Pt.png" alt="FF Image"></p>