function changeImages ( oldPicture, newPicture ) {
	for ( i=0; i<document.images.length; i++ ) {
		
		if (  document.images[i].src.substr ( document.images[i].src.length - oldPicture.length )  == oldPicture ) {
			document.images[i].src = newPicture;
			break;
		}
	}
}