longblob image not showing

Im bussy with a schoolproject and i found a problem. I can't echo a image from a dataase. The problem is that the image is saying that there is no image found. The picture is in the database and i in a object called foto.

public function getfoto() {
    require('../../config.php');
    $sql = "SELECT foto FROM producten WHERE productID = ?";
    if ($stmt = $mysqli->prepare($sql)) {
        $stmt->bind_param("i", $this->id);
        $stmt->execute();
        /* bind result variables */
        $stmt->store_result();
        $stmt->bind_result($foto);

        return '<img src="data:image/jpeg;base64,'.base64_encode($foto).'" class="thumbnail profile-img"/>';
        /* close statement */
        $stmt->close();
    }else{
        echo "Execute failed: (" . $stmt->errno . ") " . $stmt->error;  
        printf("Errormessage: %s\n", $mysqli->error);
    }
}

upload file:

  $product  = new product(null, $_POST['productnaam'], $_POST['categorie'],$_POST['omschrijving'],$_POST['min-vooraad'],$_POST['status'],$_POST['prijs']);

$foto = $mysqli->real_escape_string (addslashes(file_get_contents($_FILES["image"]["tmp_name"])));
$product->storefoto($foto);