#menu a.welcome {
  background-image: url(/gui/menu-welcome.gif);
}
#menu a.welcome:hover {
  background-image: url(/gui/menu-welcome_a.gif);
}
#menu a.showcase {
  background-image: url(/gui/menu-showcase.gif);
}
#menu a.showcase:hover {
  background-image: url(/gui/menu-showcase_a.gif);
}
#menu a.contact {
  background-image: url(/gui/menu-contact.gif);
}
#menu a.contact:hover {
  background-image: url(/gui/menu-contact_a.gif);
}