Am rezolvat cu pluginul User Role Editor WordPress › User Role Editor « WordPress Plugins , era optiunea unfiltered_html , care fara plugin trebuia sa adaug in functions.php linile astea doua :
Cod:
// get the "author" role object
$role = get_role( 'author' );

// add "organize_gallery" to this role object
$role->add_cap( 'unfiltered_html' );