def image_field(method, options = {})
      render(partial:"admin/shared/forms/image_field", locals: {
        f: self,
        method: method,
        options: options,
        preview_url: options[:preview_url]
      })
    end
def image_field(method, options = {})
      render(partial:"admin/shared/forms/image_field", locals: {
        f: self,
        method: method,
        options: options,
        preview_url: options[:preview_url]
      })
    end
Returns an image upload field with a more pleasant interface than browser
 file inputs. Changes messaging if the `method` already exists.

 #### Special Options

 - `:preview_url` If the file already exists, provide a URL to a 42×42px
   version of the image, and it will be displayed to the user in a preview
   box to better communicate which file they are replacing.

 Other options are forwarded to the hidden `file_field`.