php 图片上传源码下载[gif,jpg]

    $dest_folder   =  "/picture/";
 if(!file_exists($dest_folder)){
        mkdir($dest_folder);
 }
 foreach ($_FILES["pictures"]["error"] as $key => $error) {
     if ($error == UPLOAD_ERR_OK) {
  $houzhui=substr($_FILES["pictures"]["name"][$key],-4);
  if ($_FILES["pictures"]["size"][$key]<=1024*100) //100K
  {
  if ($houzhui==".jpg" or $houzhui==".gif")
  {
         $tmp_name = $_FILES["pictures"]["tmp_name"][$key];
         $name    = date("ymdhs")."_".mt_rand(10000,99999).$houzhui;
         $uploadfile = $dest_folder.$name;
         move_uploaded_file($tmp_name, $uploadfile);
  echo "