hacks-guide-minimal-mistakes-theme/_includes/page__hero.html

{% if page.header.image contains "http" %}
  {% capture img_path %}{{ page.header.image }}{% endcapture %}
{% else %}
  {% capture img_path %}{{ page.header.image | prepend: "/images/" | prepend: base_path }}{% endcapture %}
{% endif %}

{% if page.header.background_image contains "http" %}
  {% capture background_img_path %}{{ page.header.background_image }}{% endcapture %}
{% else %}
  {% capture background_img_path %}{{ page.header.background_image | prepend: "/images/" | prepend: base_path }}{% endcapture %}
{% endif %}

<div class="page__hero{% if page.header.splash %}--splash{% endif %}"
  style="background: {{ page.header.background_color | default: 'transparent' }} {% if background_img_path %}url('{{ background_img_path }}'){% endif %};"
>
  {% if page.header.splash %}
    <div class="wrapper">
      <h1 class="page__title" itemprop="headline">{{ page.title | markdownify | remove: "<p>" | remove: "</p>" }}</h1>
      {% if site.read_time and page.read_time %}<p class="page__meta"><i class="fa fa-clock-o" aria-hidden="true"></i> {% include read-time.html %}</p>{% endif %}
    </div>
  {% else %}
    <img src="{{ img_path }}" alt="{{ page.title }}" class="page__hero-image">
    {% if page.header.caption %}
      <span class="page__hero-caption">{{ page.header.caption | markdownify | remove: "<p>" | remove: "</p>" }}</span>
    {% endif %}
  {% endif %}
</div>