How can I optimize this function?
<p>I created a function for generating and saving multiple image sizes when a user uploads an image via a web form. I was wondering, how can I better optimize my code (reduce the number of lines while still being easily readable)</p>

<p><code>save_image($_FILES['image'], $_GET['member_id'], 250, 300, large) //usage example</code> </p>

<p>The Function</p>

<pre><code>function save_image($file, $id, $sizex, $sizey, $pre){
$image=$_FILES['image']['name'];
$tmpName = $_FILES['image']['tmp_name'];
if ($image){
    //get the original name of the file from the clients machine
        $filename = stripslashes($_FILES['image']['name']);
    //get the extension of the file in a lower case format
        $extension = getExtension($filename);
        $extension = strtolower($extension);
    if (($extension == "jpg") || ($extension == "jpeg")){
        $size = getimagesize($tmpName);
        $max_x = 180;
        $max_y = 300;
        $img = imagecreatefromjpeg($file['tmp_name']);
        $imagex = imagesx($img);
        $imagey = imagesy($img);
        $dim = max($imagex/$max_x, $imagey/$max_y);
        $nx = $imagex/$dim;
        $ny = $imagey/$dim;
        $image = imagecreatetruecolor($nx, $ny);
        imagecopyresampled($image, $img, 0, 0, 0, 0, $nx, $ny, $imagex, $imagey);
        imagejpeg($image, '../images/uploads/'.$id.'-large.jpg');
        //Make the thumb
        $size = getimagesize($tmpName);
        $max_x = 120;
        $max_y = 230;
        $img = imagecreatefromjpeg($file['tmp_name']);
        $imagex = imagesx($img);
        $imagey = imagesy($img);
        $dim = max($imagex/$max_x, $imagey/$max_y);
        $nx = $imagex/$dim;
        $ny = $imagey/$dim;
        $image = imagecreatetruecolor($nx, $ny);
        imagecopyresampled($image, $img, 0, 0, 0, 0, $nx, $ny, $imagex, $imagey);
        imagejpeg($image, '../images/uploads/'.$id.'-med.jpg');
        $size = getimagesize($tmpName);
        $max_x = 60;
        $max_y = 115;
        $img = imagecreatefromjpeg($file['tmp_name']);
        $imagex = imagesx($img);
        $imagey = imagesy($img);
        $dim = max($imagex/$max_x, $imagey/$max_y);
        $nx = $imagex/$dim;
        $ny = $imagey/$dim;
        $image = imagecreatetruecolor($nx, $ny);
        imagecopyresampled($image, $img, 0, 0, 0, 0, $nx, $ny, $imagex, $imagey);
        imagejpeg($image, '../images/uploads/'.$id.'-thumb.jpg');
    }else{
        return false;
    }
}else{
    return false;
}
return true;
}
</code></pre>
