.bgslider {
    background-image: url(_media/site/backgrounds/fungalclock2.jpg);
    background-size: cover;
    animation: animate 60s linear infinite;
    -webkit-transition: background 1.5s linear;
    -moz-transition: background 1.5s linear;
    -o-transition: background 1.5s linear;
    -ms-transition: background 1.5s linear;
    transition: background 1.5s linear;
}
    
@keyframes animate{
    0%,100%{ background-image: url(_media/site/backgrounds/fungalclock2.jpg); opacity: 1 }
    25% { background-image: url(_media/site/backgrounds/taro-mushroom1.jpg); }
    50% { background-image: url(_media/site/backgrounds/sensor.jpg);}
    75% { background-image: url(_media/site/backgrounds/taro-mushroom2.jpg);}
}

body::after{
   position:absolute; width:0; height:0; overflow:hidden; z-index:-1;
   content:url(_media/site/backgrounds/fungalclock2.jpg) url(_media/site/backgrounds/taro-mushroom1.jpg) url(_media/site/backgrounds/sensor.jpg) url(_media/site/backgrounds/taro-mushroom2.jpg);
}