Billede upload - PHP

Hej Eksperter.

Jeg sidder og leger lidt med dette script, men kan simpelthen bare ikke få det til at lykkedes.

Den uploader fint nok billedet, men den nægter at lave en thumb.

Scriptet kommer her:
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<?
$id = 1;
$picnr = 1;

$uploaddir = "billeder/"; // Mappe til færdige billeder
$maxsize = 400; // Maximum bredde/højde
$thumbmaxsize = 40; // Maximum bredde/højde
if (isset($_POST['submit']) && $_POST['submit'] == "Send Fil") {
    $source = $_FILES['upfile']['tmp_name'];
    $name = $_FILES['upfile']['name'];
    $ext = strrchr($name, '.');
    if (is_uploaded_file($source)) {
        if (tjektype($name)) {
            $dest = $uploaddir . $id . "_" . $picnr . $ext;
            $destthumb = $uploaddir . $id . "_" . $picnr . "_thumb" . $ext;
            if (move_uploaded_file($source, $dest)) {
                mainpic($dest, $maxsize);
                makethumb($destthumb, $thumbmaxsize);
                echo "Upload ok!";
                echo "<p><img src='".$dest."' alt='billede' /></p>";
                echo "<p><img src='".$destthumb."' alt='billede' /></p>";
      include("conn.php");
      $insertSQL = "insert into biler (billede1)
      values ('$dest')";
      mysql_query($insertSQL) or die(mysql_error()); 

            } else {
                echo "Ingen upload!";
            }
        } else {
            echo "Denne filtype er ikke tilladt at uploade!";
        }
    } else {
        echo "Ulovlig handling!";
    }
}

function Mainpic($sourcefile, $size) {
    $ext = strrchr($sourcefile, '.');
    if ($ext == '.png') {
        $im = imageCreateFromPNG($sourcefile);
    } elseif ($ext == '.jpg' || $ext == '.jpeg') {
        $im = imageCreateFromJPEG($sourcefile);
    }
    $source_x = imagesx($im);
    $source_y = imagesy($im);
    $delta = $size/max($source_x, $source_y);
    $dest_x = round($source_x*$delta);
    $dest_y = round($source_y*$delta);
    $target_id = imagecreatetruecolor($dest_x, $dest_y);   
    imagecopyresampled($target_id,$im,0,0,0,0, $dest_x,$dest_y, $source_x,$source_y);
    $black = imagecolorallocate ($target_id, 0, 0, 0);
    imagecolortransparent($target_id, $black);
    if ($ext == '.png') {
        imagePNG($target_id, $sourcefile);
    } elseif ($ext == '.jpg' || $ext == '.jpeg') {
        imageJPEG($target_id, $sourcefile);
    }
}

function Makethumb($sourcefile, $size) {
    $ext = strrchr($sourcefile, '.');
    if ($ext == '.png') {
        $im = imageCreateFromPNG($sourcefile);
    } elseif ($ext == '.jpg' || $ext == '.jpeg') {
        $im = imageCreateFromJPEG($sourcefile);
    }
    $source_x = imagesx($im);
    $source_y = imagesy($im);
    $delta = $size/max($source_x, $source_y);
    $dest_x = round($source_x*$delta);
    $dest_y = round($source_y*$delta);
    $target_id = imagecreatetruecolor($dest_x, $dest_y);   
    imagecopyresampled($target_id,$im,0,0,0,0, $dest_x,$dest_y, $source_x,$source_y);
    $black = imagecolorallocate ($target_id, 0, 0, 0);
    imagecolortransparent($target_id, $black);
    if ($ext == '.png') {
        imagePNG($target_id, $sourcefile);
    } elseif ($ext == '.jpg' || $ext == '.jpeg') {
        imageJPEG($target_id, $sourcefile);
    }
}

function tjektype($filnavn) {
    $ext = strrchr($filnavn, '.');
    $tilladt = array('.jpg', '.jpeg', '.png');
    if(!in_array($ext, $tilladt)) {
        return false;
    }else{
        return true;
    }
}

function tjekfil($filnavn) {
    $i = 0;
    $arr = explode(".", $filnavn);
    $ext = array_pop($arr);
    $navn = implode(".", $arr);
    $navn = str_replace(' ', '_', $navn);
    while (is_file($filnavn)) {
        $i++;
        $filnavn = $navn . "_" . sprintf("%06u", $i) . "." . $ext;
  }
    return $filnavn;
}
?>
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De kommer med fejlen:

Warning: imagecreatefromjpeg(billeder/1_1_thumb.jpg) [function.imagecreatefromjpeg]: failed to open stream: No such file or directory in /usr/home/hennings/public_html/X4/billeder_form.php on line 66

Warning: imagesx(): supplied argument is not a valid Image resource in /usr/home/hennings/public_html/X4/billeder_form.php on line 68

Warning: imagesy(): supplied argument is not a valid Image resource in /usr/home/hennings/public_html/X4/billeder_form.php on line 69

Warning: Division by zero in /usr/home/hennings/public_html/X4/billeder_form.php on line 70

Warning: imagecreatetruecolor() [function.imagecreatetruecolor]: Invalid image dimensions in /usr/home/hennings/public_html/X4/billeder_form.php on line 73

Warning: imagecopyresampled(): supplied argument is not a valid Image resource in /usr/home/hennings/public_html/X4/billeder_form.php on line 74

Warning: imagecolorallocate(): supplied argument is not a valid Image resource in /usr/home/hennings/public_html/X4/billeder_form.php on line 75

Warning: imagecolortransparent(): supplied argument is not a valid Image resource in /usr/home/hennings/public_html/X4/billeder_form.php on line 76

Warning: imagejpeg(): supplied argument is not a valid Image resource in /usr/home/hennings/public_html/X4/billeder_form.php on line 80

Det er i Makethumb den laver denne fejl.

Nogen idéer?

Mvh René