horizon/django-openstack/django_openstack/templates/django_openstack/syspanel/images/_delete.html

<form id="form_delete_{{image.id}}" class="form-delete" method="post">
  {% csrf_token %}
  {% for hidden in form.hidden_fields %}
    {{hidden}}
  {% endfor %}
  <input name="image_id" type="hidden" value="{{image.id}}" />
  <input id="delete_{{image.id}}" class="delete" title="Image: {{image.name}}" type="submit" value="Delete" />
</form>