Best practice database transactions and storing files onto filesystem in PHP

What would be the best practice regarding integrity if a user uploads user data together with a file where the user data is stored in a database and the file is stored onto the filesystem?

At the moment I would do something like the following code snippet using PHP and PDO (code is not tested, but I hope you will got my point). I don't like the save image part in the User::insert method. Is there a good way around this?

<?php
User::insert($name, $image, $ext);

Class User{
    static public function insert($name, $image, $ext){
        $conn = DB_config::get();

        $conn->beginTransaction();

        $sth = $conn->prepare("
                                INSERT INTO users (name)
                                values(:name)
                                ;");

        $sth->execute(array(
                                ":name"     =>  $name
                                ));

        if ($conn->lastInsertId() > -1 && Image::saveImage($image, IMAGE_PATH . $conn->lastInsertId(). $ext))
            $conn->commit();
        else
            $conn->rollback();

        return $conn->lastInsertId();
    }
}

Class Image{
    static public function saveimage($image, $filename){
        $ext = self::getExtensionFromFilename($filename);

        switch($ext){
            case "jpg":
            case "jpeg":
                return imagejpeg(imagecreatefromstring($image), $filename);
        }

        return false;
    }
?>