if( document.images )
{
<!--On & Off-->
  mainoff = new Image(137,17) ;
  mainoff.src = "images/but0off.gif";
  mainon = new Image(60,60) ;
  mainon.src ="images/but0on.gif"; 

  aboutoff = new Image(137,17) ;
  aboutoff.src = "images/but1off.gif";
  abouton = new Image(137,17) ;
  abouton.src ="images/but1on.gif"; 

  caloff = new Image(137,17) ;
  caloff.src = "images/but2off.gif";
  calon = new Image(137,17) ;
  calon.src ="images/but2on.gif"; 

  cmteoff = new Image(137,17) ;
  cmteoff.src = "images/but3off.gif";
  cmteon = new Image(137,17) ;
  cmteon.src ="images/but3on.gif"; 

  eduoff = new Image(137,17) ;
  eduoff.src = "images/but4off.gif";
  eduon = new Image(137,17) ;
  eduon.src ="images/but4on.gif"; 

  fotooff = new Image(137,17) ;
  fotooff.src = "images/but5off.gif";
  fotoon = new Image(137,17) ;
  fotoon.src ="images/but5on.gif"; 

  orgsoff = new Image(137,17) ;
  orgsoff.src = "images/but6off.gif";
  orgson = new Image(137,17) ;
  orgson.src ="images/but6on.gif"; 

  linkoff = new Image(137,17) ;
  linkoff.src = "images/but7off.gif";
  linkon = new Image(137,17) ;
  linkon.src ="images/but7on.gif"; 

<!--Add additional sets as needed-->
}