#slideshow {
    position: relative;
    height: 400px;
    width: 600px;
    margin: auto auto 20px
}

#slideshow img {
    position: absolute;
    top: 0;
    left: 0;
    height: 400px;
    width: 600px;
    opacity: 0;
    transition: opacity 1s;
    border-radius: 6px;
    z-index: 2
}

#slideshow img.active {
    opacity: 1
}