image1= new Image(413,279);
image1.src="images/big_image1.jpg";
image2= new Image(413,279);
image2.src="images/big_image2.jpg";
image3= new Image(413,279);
image3.src="images/big_image3.jpg";  
image4= new Image(413,279);
image4.src="images/big_image4.jpg";   
image5= new Image(413,279);
image5.src="images/big_image5.jpg";  
image6= new Image(413,279);
image6.src="images/big_image6.jpg";  

function swopImage(imageNumber) {
      imgOn=eval("image" + imageNumber + ".src");
      document["bigImage"].src= imgOn;
}