simple-s3-gallery/templates/gallery.html

<div class="album py-5 bg-body-tertiary">
  <div class="container">
    <div class="row row-cols-1 row-cols-sm-2 row-cols-md-3 g-3" data-memory='{"PercentPossition": true}'>

      {% for this in gallery_items %}
        <div class="col-md">{% include 'card.html' %}</div>
        <div class="col-md">{% include 'card_loading.html' %}</div>
      {% endfor %}

    </div>
  </div>
</div>