title: Center div inside image with flexbox
body: <p>Trying to center a div inside an image with flexbox (I only want flexbox), but since img does not have closing tag, I cannot make it work. How to do?</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>.uno {
     display: flex;
     justify-content: center;
     align-items: center;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="uno"&gt;
     &lt;img src="https://www.placecage.com/300/300" alt=""&gt;
     &lt;h1&gt;Center this text&lt;/h1&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  <p>This puts my text in the center but to the right of the img. Only flexbox solutions.</p>