$upload = new UploadFile();// 实例化上传类
$upload->maxSize = 3145728 ; // 设置附件上传大小
$upload->allowExts = array('jpg', 'gif', 'png', 'jpeg'); // 设置附件上传类型
$upload->savePath = './Uploads/img/'; // 设置附件上传目录

$upload->thumb = true;

$upload->thumbMaxWidth = ('44,100,300');
$upload->thumbMaxHeight = ('58,100,300');

$thumb_size=$upload->thumbPath='./Uploads/thumb/';
我设置了生成多张图 怎么只出现一张图