title: How to exclude django form field from render but still keep it for validation?
body: <p>If I have a model (extract):</p>
  
  <pre><code>class Coupon(models.Model):
      image = models.ImageField(max_length=64, null=True, upload_to="couponimages")
  </code></pre>
  
  <p>And a form (extract):</p>
  
  <pre><code>class InsertCoupon(forms.ModelForm):
      image=forms.ImageField(
          required=False, #note explicitly declared false
          max_length=64,
          widget=forms.FileInput() 
          )
      class Meta:
          model=Coupon,
          exclude = ("image",)
  </code></pre>
  
  <p>Then I notice that the image field is still rendered when I do <code>{{ form.as_table }}</code>. If I remove the explicit declaration of the field from the form class, then it doesn't render, but I don't get the benefit of form validation and easy modelform insertion to the database. I want to use my own widget for this field (<code>FileInput</code> is ugly) - do I have to hence code all the html myself, or is there a way to use <code>as_table</code>?</p>