$captcha = new ZendCaptchaImage(array(
        'Expiration' => '300',
        'wordlen' => '5',
        'Height' => '50',
        'Width' => '200',
        'Font' => '/usr/share/fonts/wps-office/FZSSK.TTF',
        'FontSize' => '24',
        'ImgDir' => 'data/images'
));
//设置验证码保存路径
$captcha->setImgDir(__DIR__ . '/data/');
//生成验证码
$captcha->generate();
//获取验证码内容且输出
echo $captcha->getWord();