{% load wagtailcore_tags %}
{% load wagtailimages_tags %}

<div class="card-deck">
    {% for card in self.cards %}
        {% image card.image width-400 as tmp_photo %}
        <div class="card">
            <img class="card-img-top" src="{{ tmp_photo.url }}" alt="Card image cap">
            <div class="card-body" style="background: {{ card.bg_color }}">
              <h5 class="card-title">{{ card.title }}</h5>
              <p class="card-text">{{ card.description }}</p>
            </div>
        </div>
    {% endfor %}
</div>