body {
  margin: 0;
  padding: 0;
  background: #ffffff;
}

.center {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

.slider {
  background: url(New folder/bg_1.jpg);
  background-size: cover;
  height: 450px;
  width: 800px;
  box-shadow: 0px 5px 8px rgba(255, 255, 255, 0.3);
  animation: animate 20s infinite;
}

@keyframes animate {
  16.66% {
    background: url(New folder/bg_2.jpg);
    background-size: cover;
  }
  33% {
    background: url(New folder/bg_3.jpg);
    background-size: cover;
  }
  49.99% {
    background: url(New folder/bg_4.jpg);
    background-size: cover;
  }
  66.65% {
    background: url(New folder/bg_3.jpg);
    background-size: cover;
  }
  83.31% {
    background: url(New folder/bg_2.jpg);
    background-size: cover;
  }
  100% {
    background: url(New folder/bg_1.jpg);
    background-size: cover;
  }
}