通过图片URL下载图片到本地

$imgUrl = "http://offlintab.firefoxchina.cn/static/img/search/baidu_web.png";
ob_clean();
ob_start();
readfile($imgUrl);
$img = ob_get_contents();

ob_end_clean();

$imgName = "test.jpg";    //自定义图片名称

$savePath = "./test";          //自定图片存放路径

$fp = fopen($savePath.$imgName,"w");
fwrite($fp,$img);

fclose($fp);