<?php
 /**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2015/6/29
 * Time: 22:27
 */
 $img = imagecreatefromjpeg('face.jpeg');//根据已有的JPG创建image
 header('Content-type:image/jpeg');//设置mime type
 imagestring($img,5,5,5,'Vito-L',imagecolorallocate($img,255,0,0));//生成水印，imagestring(图片,字体,位置x,位置y,字符串,颜色)
 imagejpeg($img);//输出图片
 //整幅图像的左上角为 0，0