Multiple file upload.

Vha. nedenstående script uploader jeg et billed, laver en thumb og skriver data til databasen.
Jeg kunne rigtigt godt tænke mig at kunne uploade flere filer på en gang.
Jeg forestiller mig at man vha. en variable angiver hvor mange filer der skal kunne uploades (så det er nemt at ændre), men da jeg er relativ ny udi PHP verdenen, er jeg lidt usikker på hvordan.
Jeg tror nu nok at jeg kan lave et loop der skriver x antal felter i formen, men hvordan skal jeg navngive dem, og hvordan sikrer jeg mig at scriptet efterfølgende uploader alle filerne og i øvrigt ignorerer eventuelle blanke felter.

///////////// SCRIPT START ///////////////
<?php
include("connection.php");

$updir = "upload/";  // Definer stien til dit oploadbibliotek
$aft = array('image/jpeg','image/pjpeg','image/png'); // De filtyper der kan uploades

/*
    Function checkgd()
    checks the version of gd, and returns "yes" when it's higher than 2
*/
function checkgd(){
    $gd2="";
    ob_start();
    phpinfo(8);
    $phpinfo=ob_get_contents();
    ob_end_clean();
    $phpinfo=strip_tags($phpinfo);
    $phpinfo=stristr($phpinfo,"gd version");
    $phpinfo=stristr($phpinfo,"version");
    preg_match('/\d/',$phpinfo,$gd);
    if ($gd[0]=='2'){$gd2="yes";}
    return $gd2;
}

/*
    Function createthumb($name,$filename,$new_w,$new_h, $updir)
    creates a resized image
    variables:
    $name        Original filename
    $filename    Filename of the resized image
    $new_w        width of resized image
    $new_h        height of resized image
*/   
function createthumb($name,$filename,$new_w,$new_h,$updir){

    global $gd2;
    $system=explode(".",$name);

    if (preg_match("/jpg|jpeg/",$system[1])){$src_img=imagecreatefromjpeg($name);}
    if (preg_match("/png/",$system[1])){$src_img=imagecreatefrompng($name);}
    $old_x=imageSX($src_img);
    $old_y=imageSY($src_img);
    if ($old_x > $old_y) {
        $thumb_w=$new_w;
        $thumb_h=$old_y*($new_h/$old_x);
    }
    if ($old_x < $old_y) {
        $thumb_w=$old_x*($new_w/$old_y);
        $thumb_h=$new_h;
    }
    if ($old_x == $old_y) {
        $thumb_w=$new_w;
        $thumb_h=$new_h;
    }
    if ($gd2==""){
        $dst_img=ImageCreate($thumb_w,$thumb_h);
        imagecopyresized($dst_img,$src_img,0,0,0,0,$thumb_w,$thumb_h,$old_x,$old_y);
    }else{
        $dst_img=ImageCreateTrueColor($thumb_w,$thumb_h);
        imagecopyresampled($dst_img,$src_img,0,0,0,0,$thumb_w,$thumb_h,$old_x,$old_y);
    }
    if (preg_match("/png/",$system[1])){
        imagepng($dst_img,$filename);
    } else {
        imagejpeg($dst_img,$filename);
    }
    imagedestroy($dst_img);
    imagedestroy($src_img);
}


?>
<html>
<head>
<title>Untitled Document</title>
<link href="scroll.css" type="text/css" rel="stylesheet">
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>

<body bgcolor="#D0D0D0" text="#000000">
<font face="Verdana, Arial, Helvetica, sans-serif" size="2">upload</font>
<br><br>
<?php
if (isset($_GET['mode']) && $_GET['mode'] == "upload") {
    $galleri = $_POST['ddgalleri'];
    $newfilename = $updir.$galleri."_".$_FILES['fil']['name'];
    $newfilename = strtolower($newfilename);
    $newthumb = $updir."thumbs/thumb_".$galleri."_".$_FILES['fil']['name'];
    $newthumb = strtolower($newthumb);

    if (empty($_REQUEST['fil'])) {
        echo "Du skal vælge en fil";
    }
    else {

      if (in_array($_FILES['fil']['type'],$aft)) {
      if (move_uploaded_file($_FILES['fil']['tmp_name'], $newfilename)) {
        $gd2=checkgd();
        createthumb($newfilename, $newthumb,100,100,$updir);

        $imginfo = getimagesize($newfilename);
        $imgwidth = $imginfo[0];  //bredde i pixels
        $imgheight = $imginfo[1]; //højde i pixels
        $imgtype = $imginfo[2];  //jpg, gif, bmp osv
        $imghtml = $imginfo[3];  //height="yyy" width="xxx" - for use directly in html
   
    $billede = explode("/",$newfilename);

    $tekst = $_POST['tekst'];
    $strSQL = "insert into galleripics (galleriid, billed, tekst, width, height) VALUES ";
    $strSQL = $strSQL."('".$galleri."', '".$billede[1]."', '".$tekst."', '".$imgwidth."', '".$imgheight."')";
    echo $strSQL;

            }
            else {}
        }
        else {
              echo "Filtypen er ikke korrekt!";
        }   
    }

}

elseif (empty($_GET['mode'])) {
    ?>

    <form action="test2.php?mode=upload" method="post" enctype="multipart/form-data">
    <input type="hidden" name="MAX_FILE_SIZE" value="100000">
    <?php
    $res = mysql_query("SELECT * FROM gallerier");
    echo "<select name=ddgalleri size=1>";
    while($row = mysql_fetch_array($res)) {
    echo "<option value=".$row["galleriid"].">".$row["galleri"]."</option>";
    }
    echo "</select><br />";

    mysql_close();
    ?>
    <input type="file" name="fil"><br />
    <input type="text" name="tekst">
    <br /><br />
    <input type="submit" name="submit" value="Upload" >
    </form>

    <?php

}
else {
    echo "Bad guy!";
}
?>

</body>
</html>
////////////// SCRIPT SLUT //////////////