imagecreatefromjpeg（）：gd-jpeg：JPEG

$filename = 'upload/'.date("Y-m").'/small_'.$pathinfo['basename'];

$typeArr=explode(".",$filename);

switch($typeArr['1'])
{
case "png":
$img_r=imagecreatefrompng($src);
break;

case "jpg":
$img_r=imagecreatefromjpeg($src);
break;
case "jpeg":
$img_r=imagecreatefromjpeg($src);
break;

case "gif":
$img_r=imagecreatefromgif($src);
break;
}

//只能处理jpg图像
//$img_r = imagecreatefromjpeg($src); //从url新建一图像