{% load static %}
 <form method="post" action="{% url 'social:begin' name %}">
    {% csrf_token %}
    {% with "umap/img/providers/"|add:name|add:".png" as path %}
    <button type="submit">
      <img src="{% static path %}" width="92px" height="92px" alt="{{ name }}" />
    </button>
    {% endwith %}
</form>