public function getPermittedDimensions(): array
    {
        $aDimensions = array_map(function ($sDimension) {
            return (object) array_combine(
                ['width', 'height'],
                array_map('intval', explode('x', $sDimension))
            );
        }, $this->aPermittedDimensions);

        arraySortMulti($aDimensions, 'width');

        return array_values($aDimensions);
    }