childImage = new Array();
childImage[0] =  'images/01.jpg';
childImage[1] =  'images/02.jpg';

var p = childImage.length;

var whichChildImage = Math.round(Math.random()*(p-1));

function writeChildImage() {
	document.write('<img src="'+ childImage[whichChildImage]+'" width="223px" />');
}