function VerImagenes()
{
	var unaImagen;
	var imagenes = new Array("img_01.gif", "img_02.gif", "img_11.gif", "img_04.gif", "img_05.gif", "img_06.gif", "img_07.gif", "img_12.gif", 			                             "img_13.gif", "img_14.gif", "img_15.gif", "img_16.gif", "img_08.gif", "img_09.gif", "img_17.gif");

	var id_imgs = new Array('img1', 'img2', 'img3', 'img4');
	
	for(var i=0; i < id_imgs.length; i++) {
		var numero = Math.floor(Math.random() * imagenes.length);
		unaImagen = document.getElementById(id_imgs[i]);
		unaImagen.src = imagenes[numero];
		imagenes.splice(numero,1);
	}
}