<div class="slider">
  <figure class="circle">
    <img class="image" src="//placehold.it/300x300?text=1" alt="">
  </figure>
  <figure class="circle">
    <img class="image" src="//placehold.it/300x300?text=2" alt="">
  </figure>
  <figure class="circle">
    <img class="image" src="//placehold.it/300x300?text=3" alt="">
  </figure>
  <figure class="circle">
    <img class="image" src="//placehold.it/300x300?text=4" alt="">
  </figure>
</div>

* {
  box-sizing: border-box;
}

body {
  display: flex;
  background-color: #ff9800;
  margin: 0;
  height: 100vh;
}

.slider {
  position: relative;
  width: 90vmin;
  margin: auto;
  border-radius: 50%;
  overflow: hidden;
}

.slider::before  {
  content: '';
  position: absolute;
  width: 100%;
  height: 100%;
  background:
    radial-gradient(circle farthest-side, #ff9800 25%, transparent calc(25% + 1px)),
    linear-gradient(-45deg, transparent 50%, #ff9800 calc(50% + 1px)),
    linear-gradient(45deg, #ff9800 50%, transparent calc(50% + 1px));
  z-index: 1;
}

.slider::after {
  content: '';
  display: block;
  padding-bottom: 100%;
}

.circle {
  position: absolute;
  width: 100%;
  height: 100%;
  margin: 0;
  animation: opac 8s step-end infinite;
}

.circle:nth-child(1) {
  animation-delay: -8s;
}

.circle:nth-child(2) {
  animation-delay: -6s;
}

.circle:nth-child(3) {
  animation-delay: -4s;
}

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

.circle::before {
  content: '';
  position: absolute;
  width: 100%;
  height: 100%;
  background:
    linear-gradient(-45deg, transparent 50%, #ff9800 calc(50% + 1px)),
    linear-gradient(45deg, #ff9800 50%, transparent calc(50% + 1px));
  transform: rotate(90deg);
  animation: rotate 8s ease-in-out infinite;
}

.circle:nth-child(1)::before {
  animation-delay: -8s;
}

.circle:nth-child(2)::before {
  animation-delay: -6s;
}

.circle:nth-child(3)::before {
  animation-delay: -4s;
}

.circle:nth-child(4)::before {
  animation-delay: -2s;
}

.image {
  display: block;
  margin-left: 50%;
  width: 50%;
  height: 100%;
  object-fit: cover;
}

@keyframes rotate {
  0% {
    transform: rotate(90deg);
  }
  
  7%, 18% {
    transform: rotate(0);
  }
  
  25%, 100% {
    transform: rotate(-90deg);
  }
}

@keyframes opac {
  0% {
    opacity: 1;
  }
  25%, 100% {
    opacity: 0;
  }
}