if (document.images)
   {
     pic1on= new Image(100,25);
     pic1on.src="images/thumbs/sitting1.gif";
     
     pic1off= new Image(100,25);
     pic1off.src="images/thumbs/sitting.gif";   
	 
	  pic2on= new Image(100,25);
     pic2on.src="images/thumbs/kitchen1.gif";
     
     pic2off= new Image(100,25);
     pic2off.src="images/thumbs/kitchen.gif";  
	 
	  pic3on= new Image(100,25);
     pic3on.src="images/thumbs/bathroom1.gif";
     
     pic3off= new Image(100,25);
     pic3off.src="images/thumbs/bathroom.gif";  
	 
	  pic4on= new Image(100,25);
     pic4on.src="images/thumbs/bedrooms1.gif";
     
     pic4off= new Image(100,25);
     pic4off.src="images/thumbs/bedrooms.gif";  
	 
	  pic5on= new Image(100,25);
     pic5on.src="images/thumbs/garden1.gif";
     
     pic5off= new Image(100,25);
     pic5off.src="images/thumbs/garden.gif";    
   }

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

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