Custom Logos for Login page and Admin in wordpress

function custom_admin_logo() {
    echo '
        <style type="text/css">
            #header-logo { background-image: url('.get_bloginfo('template_directory').'/path/to/images/admin-logo.png) !important; }
        </style>
    ';
}

add_action('admin_head', 'custom_admin_logo');

function custom_login_logo() {
    echo '<style type="text/css">
        h1 a { background-image:url('.get_bloginfo('template_directory').'/path/to/images/login-logo.png) !important; }
    </style>';
}

add_action('login_head', 'custom_login_logo');