function swap(i,n) 
{	
	if (n==0) return
	switch (i) 
	{
		case 1 :
			if (flag1) 			
			{
				flag1 = false;
		        document.images[2].src = images[0].src;
				document.images[4].src = images[n+2].src;
			}
			else 
			{
				flag1 = true;
				flag2 = false;
				flag3 = false;
				document.images[2].src = images[1].src;
				document.images[4].src = images[n+1].src;
			    if (n>1) document.images[6].src = images[n+3].src;
				if (n>2) document.images[8].src = images[n+4].src;
			}
			break;
		case 2 :
			if (flag2)
			{
				flag2 = false;
				document.images[2].src = images[0].src;
				document.images[6].src = images[n+3].src;
			}
			else 
			{
				flag2 = true;
				flag1 = false;
				flag3 = false;
				document.images[2].src = images[2].src;
				document.images[6].src = images[n+1].src;
				document.images[4].src = images[n+2].src;
				if (n>2) document.images[8].src = images[n+4].src;
			}
			break;
		case 3 :
			if (flag3) 
			{
				flag3 = false;
				document.images[2].src = images[0].src;
				document.images[8].src = images[n+4].src;
			}
			else
			{
				flag3 = true;
				flag1 = false;
				flag2 = false;
				document.images[2].src = images[3].src;
				document.images[8].src = images[n+1].src;
				document.images[4].src = images[n+2].src;
				document.images[6].src = images[n+3].src;
			}
			break;
			default : break;	
	}
}