Sandbox — JR Design House

.image-slider {
  position: relative;
  width: 100%;
  max-width: 800px;
  margin: 0 auto;
}

.image-slider img {
  width: 100%;
  height: auto;
  display: block;
}

.slider {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 10px;
  height: 100%;
  background-color: #fff;
  cursor: ew-resize;
  z-index: 10;
}

.image-slider:hover .slider {
  width: 30px;
}

.image-slider:hover img {
  filter: grayscale(100%);
}

.image-slider:hover img:last-of-type {
  filter: grayscale(0);
}