Untitled

#login-bg
{

    background-image:url('/images/login/login_background.jpg');
    font-size: 20px;
}

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">

<head>

<link rel="stylesheet" type="text/css" href="styles.css" />

</head>

<body id="login-bg">

<form action="" method="POST">

Username:  <input type="text" name="username" >
<br>
Password:  <input type="text" name="password" >
<br>
<input type="submit" value="enter">

</form>

</body>
</html>

#login-bg
{

    background-image:url('images/login/login_background.jpg');
    font-size: 20px;
}

background-image:url('images/login/login_background.jpg');