.banner{
	width: 900px;
	height: 300px;
	border: 3px;
	border-style: solid;
	border-color: rgb(255,255,255);  
	background-size: 100% 100%;
    -webkit-animation: banner 30s infinite;
}
@keyframes banner{
	0%, 20% {
		opacity: 1;
		background-image: url(imagenes/1.jpg);
	}
	21%, 24% {
		opacity: 0.1;
	}
	25%, 45% {
		opacity: 1;
		background-image: url(imagenes/2.jpg);
	}
	46%, 49% {
		opacity: 0.1;
	}
	50%, 70% {
		opacity: 1;
		background-image: url(imagenes/3.jpg);
	}
	71%, 74% {
		opacity: 0.1;
	}
	75%, 100% {
		opacity: 1;
		background-image: url(imagenes/4.jpg);
	}
}