function ImageArray(){ 
	this.length = ImageArray.arguments.length; 
	
	for (var i = 0; i < this.length; i++) { 
		this[i] = new Image();
		this[i].src = ImageArray.arguments[i];
		} 
	} 

function SwapImage( objId, img ){
   	document.getElementById(objId).src = img;
	}

var imgs = new ImageArray('images/tower_north.jpg','images/tower_north_a.jpg','images/tower_north_b.jpg','images/tower_north_c.jpg',
						  'images/tower_south.jpg','images/tower_south_d.jpg','images/tower_south_e.jpg','images/tower_south_f.jpg',
                          'images/tower_south_g.jpg','images/tower_north_sm.jpg','images/tower_north_sm_a.jpg','images/tower_north_sm_b.jpg',
                          'images/tower_north_sm_c.jpg','images/tower_sm_south.jpg','images/tower_south_sm_d.jpg','images/tower_south_sm_e.jpg',
                          'images/tower_south_sm_f.jpg','images/tower_south_sm_g.jpg');

function openWin(url, params){
	var params = (params != '' ? params+',' : '')+'scrollbars=1,top=0,left=0,location=0';
	window.open(url, 'OpenWin', params);
	}