code: def customize_form_field(self, name, field):
          
          if isinstance(field, forms.fields.DateField) and isinstance(field.widget, forms.widgets.DateInput):
              field.widget = widgets.DatePickerWidget()
              field.input_formats = [field.widget.input_format[1]] + list(field.input_formats)
  
          if isinstance(field, forms.fields.ImageField) and isinstance(field.widget, forms.widgets.ClearableFileInput):
              field.widget = widgets.ImageThumbnailWidget()
  
          return field
docs: Allows views to customize their form fields.  By default, Smartmin replaces the plain textbox
          date input with it's own DatePicker implementation.