created_at = models.DateTimeField(_('creation date'), auto_now_add=True, db_index=True)
changed_at = models.DateTimeField(_('creation date'), auto_now=True, db_index=True)
xml_file = models.FileField(_('xml file'), upload_to="xml", storage=picture_storage)
image_file = ImageField(_('image file'), upload_to="images", storage=picture_storage)
html_file = models.FileField(_('html file'), upload_to="html", storage=picture_storage)
created_at = models.DateTimeField(_('creation date'), auto_now_add=True, db_index=True)
changed_at = models.DateTimeField(_('creation date'), auto_now=True, db_index=True)
xml_file = models.FileField(_('xml file'), upload_to="xml", storage=picture_storage)
image_file = ImageField(_('image file'), upload_to="images", storage=picture_storage)
html_file = models.FileField(_('html file'), upload_to="html", storage=picture_storage)