глючная форма из модели

class ImageStore(models.Model):
    img = models.ImageField('image', max_length=1000, 
            height_field='height', width_field='width', 
            upload_to='img/uploads/%Y/%m/%d', blank=True, null=True)
    height = models.PositiveIntegerField(null=True, blank=True, 
            editable=False)
    width = models.PositiveIntegerField(null=True, blank=True, 
            editable=False)
    alt = models.CharField('alter/title text', max_length=255)
    product = models.ForeignKey(Product)


class ImageForm(forms.ModelForm):
    class Meta:
        model = ImageStore

    def __init__(self, product=None, *args, **kwargs):
        super(ImageForm, self).__init__(*args, **kwargs)
        if product is not None:
            self.product = product
            del self.fields['product']

    def save(self, id=None, commit=True):
        if id is None:
            instance = ImageStore(product=self.product)
        else:
            instance = ImageStore.objects.get(pk=id)
        return forms.save_instance(self, instance, commit=commit)