{% load wagtailimages_tags %}

<div class="media {{self.custom_class}}">
  {% image self.media_img original as tmp_photo %}
  <img class="mr-3" src="{{tmp_photo.url}}" style="width:{{self.media_img_width}};height:{{self.media_img_height}};" alt="{{self.media_img_alt}}">
  <div class="media-body">
    <h5 class="mt-0">{{self.heading_text}}</h5>
    {{self.body_text}}
  </div>  
</div>