How do I print a notice only on certain admin pages?

I’m writing a plugin which would print a notice, but only on the media page. I found the admin_notices and all_admin_notices actions, but these are fired on all admin pages. Is there any way to find which admin page is the hook being called on from within the callback?

There is a global variable called $pagenow for the use within WP Admin:

global $pagenow;
if ( $pagenow == 'upload.php' ) :

    function custom_admin_notice() {
        echo '<div class="updated"><p>Updated!</p></div>';
    }
    add_action( 'admin_notices', 'custom_admin_notice' );

endif;

UPDATE: Simply include the snippet in your themes or plugins functions.php