title: Django ImageField not rendering ClearableFileInput
body: <p>Starting to beat my head against the wall...perhaps I am missing something simple.</p>
  
  <p><strong>models.py</strong></p>
  
  <pre><code>class GFImage(models.Model):
      image = models.ImageField(upload_to = 'uploads', null=True, blank=True)
  </code></pre>
  
  <p><strong>views.py</strong></p>
  
  <pre><code>def addImage(request):
  errors = []
  if request.method == 'POST':
      form = ImageForm(request.POST, request.FILES)
      if form.is_valid():
          form.save()
          urlRedirect = "/home"
          return redirect(urlRedirect)
  else:
      form = ImageForm()
  return render(request, "/add_image.html", {'form': form})
  </code></pre>
  
  <p><strong>forms.py</strong></p>
  
  <pre><code>class ImageForm(ModelForm):
      class Meta:
          model = GFImage
  </code></pre>
  
  <p><strong>add_image.html</strong></p>
  
  <pre><code>&lt;form method="POST" enctype="multipart/form-data"&gt;
      {% csrf_token %}
      &lt;table&gt;
          {{ form.as_table }}
      &lt;/table&gt;
      &lt;input type = "submit" value = "Submit"&gt;
  
  &lt;/form&gt;
  </code></pre>
  
  <p>Whatever I do, my form will not use the ClearableFileInput widget. It should default automatically, but even assigning it in the form's META will not work. What else could be blocking Django from using the clearable widget?</p>