window.addEventListener ? window.addEventListener('load', function() {
	ray.rand('thisCell');
}, false) : window.attachEvent('onload', function() {
	ray.rand('thisCell');
});

var ray =
{
	bgArr : [ 'url(./BigImage_Chair.jpg)',
			'url(./BigImage_Container.jpg)',
			'url(./BigImage_Dive.jpg)',
			'url(./BigImage_Forrest.jpg)',
			'url(./BigImage_Holiday.jpg)', 
			'url(./BigImage_Kip.jpg)',
			'url(./BigImage_OneWay.jpg)' ], // Background you wish to
													// show on the cell
	rand : function(el) {
		var num = Math.floor(Math.random() * this.bgArr.length);
		this.getID(el).style.background = this.bgArr[num];
	},
	getID : function(el) {
		return document.getElementById(el);
	}
}