var images = new Array();
var shown = Array();

images[0] = new Image;
images[0].src = 'images/photo_1.jpg';
images[1] = new Image;
images[1].src = 'images/photo_1a.jpg';
images[2] = new Image;
images[2].src = 'images/photo_2.jpg';
images[3] = new Image;
images[3].src = 'images/photo_2a.jpg';
images[4] = new Image;
images[4].src = 'images/photo_3.jpg';
images[5] = new Image;
images[5].src = 'images/photo_3a.jpg';
images[6] = new Image;
images[6].src = 'images/photo_4.jpg';
images[7] = new Image;
images[7].src = 'images/photo_5.jpg';
images[8] = new Image;
images[8].src = 'images/photo_6.jpg';

function showImage() {
	var redo = true;
	var p = images.length;
	var i = 0;
	while(redo == true) {
		redo = false;
		which = Math.round(Math.random() * (p - 1));
		for(i = 0; i < shown.length; i++) {
			if(shown[i] == which) { 
				redo = true;
				break;
			}
		}
	}
	shown[shown.length] = which;
	document.write('<img src="'+ images[which].src +'" />');
}