建议检查下你每个参数的拼写，我上次是因为content-tpye拼错了导致的乱码，你可能也哪里拼错了

看看我的这个怎么样

function verifyImage($type = 1,$length = 4,$pixel = 0,$line = 0,$sess_name = "verify"){

    //通过GD库做验证码

    //创建画布

    $width = 80;

    $height = 28;

    $image = imagecreatetruecolor($width, $height);

    //创建颜色

    $white = imagecolorallocate($image, 255, 255, 255);

    $black = imagecolorallocate($image, 0, 0, 0);

    //用填充矩形填充画布

    imagefilledrectangle($image, 1, 1, $width-2, $height-2, $white);

    $chars = buildRandomString($type,$length);

    $_SESSION[$sess_name] = $chars;

    //存放字体我文件

    $fontfiles = array("MSYH.TTC","SIMYOU.TTF");

    for ($i = 0; $i < $length; $i++){

        $size = mt_rand(14, 18);

        $angle = mt_rand(-15, 15);

        $x = 5 + $i*$size;

        $y = mt_rand(20, 26);

        $fontfile = "../fonts/".$fontfiles[mt_rand(0, count($fontfiles)-1)];

        $color = imagecolorallocate($image, mt_rand(50, 90), mt_rand(80, 200), mt_rand(90, 180));

        $text = substr($chars, $i, 1);

        imagettftext($image, $size, $angle, $x, $y, $color, $fontfile, $text);

    }

    if ($pixel){

        for ($i = 0; $i < $pixel; $i++){

            imagesetpixel($image, mt_rand(0, $width-1), mt_rand(0, $height-1), $black);

        }

    }

    if ($line){

        for ($i = 0; $i < $line; $i++){

            $color = imagecolorallocate($image, mt_rand(100, 200), mt_rand(80, 200), mt_rand(100, 180));

            imageline($image, mt_rand(0, $width-1), mt_rand(0, $height-1), mt_rand(0, $width-1), mt_rand(0, $height-1), $color);

        }

    }

    header("content-type: image/gif");

    //显示画布

    imagegif($image);

    //销毁资源

    imagedestroy($image);

}

/**

 * 生成验证码

 * @param int $type

 * @param int $length

 * @return string

 */

function buildRandomString($type=1,$length=4){

if ($type == 1) {

$chars = join ( "", range ( 0, 9 ) );

} elseif ($type == 2) {

$chars = join ( "", array_merge ( range ( "a", "z" ), range ( "A", "Z" ) ) );

} elseif ($type == 3) {

$chars = join ( "", array_merge ( range ( "a", "z" ), range ( "A", "Z" ), range ( 0, 9 ) ) );

}

if ($length > strlen ( $chars )) {

exit ( "字符串长度不够" );

}

$chars = str_shuffle ( $chars );

return substr ( $chars, 0, $length );

}