How to resize image in php codeigniter

    // Configuration.
    $config['image_library'] = 'gd2';
    $config['source_image'] = './img/images/uploaded/'.$ imgName.". jpeg";
    $config['new_image'] = './img/images/uploaded/'.$ imgName." _new.jpeg";
    $config['create_thumb'] = TRUE;
    $config['maintain_ratio'] = TRUE;
    $config['width'] = 50;
    $config['height'] = 50;