Сам спросил, сам отвечаю (может кому пригодится).
Открываем /applications/gallery/modules/front/gallery/browse.php
Находим
/* Build table */
$table = new \IPS\gallery\Image\Table( 'IPS\gallery\Image', $category->url(), array( array( 'image_album_id=?', 0 ) ), $category );
$table->limit = 50;
$table->tableTemplate = array( \IPS\Theme::i()->getTemplate( 'browse' ), 'imageTable' );
$table->rowsTemplate = array( \IPS\Theme::i()->getTemplate( 'browse' ), $this->getTableRowsTemplate() );
$table->title = \IPS\Member::loggedIn()->language()->pluralize( \IPS\Member::loggedIn()->language()->get('num_images'), array( $category->count_imgs ) );
Заменяем на
/* Build table */
$table = new \IPS\gallery\Image\Table( 'IPS\gallery\Image', $category->url(), array( array( 'image_album_id=?', 0 ) ), $category );
$table->limit = 50;
$table->sortBy = \IPS\Request::i()->sortby ? $table->sortBy : 'image_date';
$table->sortDirection = \IPS\Request::i()->sortdirection ? $table->sortDirection : 'desc';
$table->tableTemplate = array( \IPS\Theme::i()->getTemplate( 'browse' ), 'imageTable' );
$table->rowsTemplate = array( \IPS\Theme::i()->getTemplate( 'browse' ), $this->getTableRowsTemplate() );
$table->title = \IPS\Member::loggedIn()->language()->pluralize( \IPS\Member::loggedIn()->language()->get('num_images'), array( $category->count_imgs ) );
Для сортировки по "Старизне" вместо
$table->sortDirection = \IPS\Request::i()->sortdirection ? $table->sortDirection : 'desc';
Пишем
$table->sortDirection = \IPS\Request::i()->sortdirection ? $table->sortDirection : 'asc';