html,
body {
    margin: 0;
    padding: 0;
}

@keyframes crossfade {
    0%, 100% {
        opacity: 0;
    }

    25%, 75% {
        opacity: 1;
    }
}

.container {
    position: relative;
    width: 336px;
    height: 236px;
    overflow: hidden;
}

.container img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: block;
    animation: crossfade 8s infinite;
}

.container img:nth-child(1) {
    animation-delay: 0s;
}

.container img:nth-child(2) {
    animation-delay: 4s;
}