系统目录下，新建images文件夹，放入图片
<html>
<head>
<title>使用PHP给图片加水印</title>
</head>
<body>
<span>虾米大王使用PHP给图片加水印</span>
<hr>
<table>
<tr>
<td>原图：</td>
<td>加水印后的图片：</td>
</tr>
<tr>
<td><img src="images/cat.jpeg" width="600" height="600"></td>
<td><img src="images/cat_water.jpeg" width="600" height="600"></td>
</tr>
</table>
</body>
</html>
<?php
$image = imagecreatefromjpeg('images/cat.jpeg');
$watermark = imagecreatefrompng('images/gua.png');
$width = imagesx($watermark);
$height = imagesy($watermark);
imagecopyresampled($image,$watermark,60,250,0,0,
($width * 0.3),($height * 0.3),$width,$height);
imagejpeg($image,'images/cat_water.jpeg'); //保存图片
imagedestroy($image);
imagedestroy($watermark);
?>