var imagenumber = 4 ;
var randomnumber = Math.random() ;
var rand1 = Math.round( (imagenumber-1) * randomnumber) + 1 ;
images = new Array;
images[1] = "picture1.gif";
images[2] = "picture15.gif";
images[3] = "picture16.gif";
images[4] = "picture17.gif";
var scimage = images[rand1];

if (document.images) {
   img01on = new Image();   img01on.src = "images/home_on.gif";
   img02on = new Image();   img02on.src = "images/aboutus_on.gif";
   img03on = new Image();   img03on.src = "images/services_on.gif";
   img04on = new Image();   img04on.src = "images/board_on.gif";
   img05on = new Image();   img05on.src = "images/members_on.gif"; 
   img06on = new Image();   img06on.src = "images/calendar_on.gif";
   img07on = new Image();   img07on.src = "images/links_on.gif";
   img08on = new Image();   img08on.src = "images/contactus_on.gif";
      
   img01off = new Image();   img01off.src = "images/home.gif";
   img02off = new Image();   img02off.src = "images/aboutus.gif";
   img03off = new Image();   img03off.src = "images/services.gif";
   img04off = new Image();   img04off.src = "images/board.gif";
   img05off = new Image();   img05off.src = "images/members.gif";
   img06off = new Image();   img06off.src = "images/calendar.gif";
   img07off = new Image();   img07off.src = "images/links.gif";
   img08off = new Image();   img08off.src = "images/contactus.gif";   
   
}

function imgOn(imgName)
{
   if (document.images) {
      document[imgName].src = eval(imgName + "on.src");
   }
}

function imgOff(imgName)
{
   if (document.images) {
      document[imgName].src = eval(imgName + "off.src");
   }
}