bulma/docs/_includes/index/sponsor.html

<div class="bd-sponsor">
  <p class="bd-sponsor-title">Sponsors</p>
  <div class="bd-sponsor-list">
    <a href="https://themeisle.com/" target="_blank" rel="nofollow">
      <img src="{{ site.url }}/images/sponsors/themeisle.png" alt="themeisle logo">
    </a>
    <a href="https://chainaxe.io/" target="_blank" rel="nofollow">
      {%
        include elements/responsive-image.html
        path="sponsors/chainaxe"
        extension="png"
        alt="chainaxe logo"
        width="99"
        height="70"
      %}
    </a>
    <a href="https://www.keycdn.com/" target="_blank" rel="nofollow">
      {%
        include elements/responsive-image.html
        path="sponsors/keycdn"
        extension="png"
        alt="keycdn logo"
        width="200"
        height="58"
      %}
    </a>
    <a href="http://tooltwist.com/" target="_blank" rel="nofollow">
      {%
        include elements/responsive-image.html
        path="sponsors/tooltwist"
        extension="png"
        alt="tooltwist logo"
        width="200"
        height="64"
      %}
    </a>
  </div>
</div>