if (document.images) {

		logobuttonup       = new Image();
    logobuttonup.src   = "pic/framework/nav_logo.jpg" ;
    logobuttondown     = new Image() ;
    logobuttondown.src =  "pic/framework/nav_logo.jpg" ;

		homebuttonup       = new Image();
    homebuttonup.src   = "pic/framework/homebuttonup.jpg" ;
    homebuttondown     = new Image() ;
    homebuttondown.src = "pic/framework/homebuttondown.jpg" ;
	  
		missionbuttonup       = new Image();
    missionbuttonup.src   = "pic/framework/missionbuttonup.jpg" ;
    missionbuttondown     = new Image() ;
    missionbuttondown.src = "pic/framework/missionbuttondown.jpg" ;
		
		photosbuttonup       = new Image();
    photosbuttonup.src   = "pic/framework/photosbuttonup.jpg" ;
    photosbuttondown     = new Image() ;
    photosbuttondown.src = "pic/framework/photosbuttondown.jpg" ;
		
		helpbuttonup       = new Image();
    helpbuttonup.src   = "pic/framework/helpbuttonup.jpg" ;
    helpbuttondown     = new Image() ;
    helpbuttondown.src = "pic/framework/helpbuttondown.jpg" ;
		
		aboutbuttonup       = new Image();
    aboutbuttonup.src   = "pic/framework/aboutbuttonup.jpg" ;
    aboutbuttondown     = new Image() ;
    aboutbuttondown.src = "pic/framework/aboutbuttondown.jpg" ;
		
		newsbuttonup       = new Image();
    newsbuttonup.src   = "pic/framework/newsbuttonup.jpg" ;
    newsbuttondown     = new Image() ;
    newsbuttondown.src = "pic/framework/newsbuttondown.jpg" ;
		
		newsletterbuttonup       = new Image();
    newsletterbuttonup.src   = "pic/framework/newsletterbuttonup.jpg" ;
    newsletterbuttondown     = new Image() ;
    newsletterbuttondown.src = "pic/framework/newsletterbuttondown.jpg" ;
		
		booksbuttonup       = new Image();
    booksbuttonup.src   = "pic/framework/booksbuttonup.jpg" ;
    booksbuttondown     = new Image() ;
    booksbuttondown.src = "pic/framework/booksbuttondown.jpg" ;
}

function buttondown( buttonname )
{
    if (document.images) {
      document[ buttonname ].src = eval( buttonname + "down.src" );
    }
}
function buttonup ( buttonname )
{
    if (document.images) {
      document[ buttonname ].src = eval( buttonname + "up.src" );
    }
}