function grabImage($url, $filename = ”) {


if($url == ”) {


return false; //如果 $url 为空则返回 false;


}


$ext_name = strrchr($url, ‘.’); //获取图片的扩展名


if($ext_name != ‘.gif’ && $ext_name != ‘.jpg’ && $ext_name != ‘.bmp’ && $ext_name != ‘.png’) {


return false; //格式不在允许的范围


}


if($filename == ”) {


$filename = time().$ext_name; //以时间戳另起名


}


//开始捕获


ob_start();


readfile($url);


$img_data = ob_get_contents();


ob_end_clean();


$size = strlen($img_data);


$local_file = fopen($filename , ‘a’);


fwrite($local_file, $img_data);


fclose($local_file);


return $filename;


}