//php自带函数 getimagesize()
//by www.qzphp.cn
$img_info = getimagesize('test.jpg');
echo '<pre>';
print_r($img_info);print_r($img_info);
输出:
//by www.qzphp.cn Array ( [0] => 170 [1] => 254 [2] => 2 [3] => width="170" height="254" [bits] => 8 [channels] => 3 [mime] => image/jpeg )
这次要用到的就是第四个元素了

