body {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
      -ms-flex-align: center;
          align-items: center;
  -webkit-box-pack: center;
      -ms-flex-pack: center;
          justify-content: center;
  height: 100vh;
  background: #111;
}

.image {
  --width: 794px;
  --height: 446px;
  position: relative;
  width: var(--width);
  height: var(--height);
  overflow: hidden;
}
.image__img {
  position: absolute;
  height: 100%;
  background: url("https://www.planwallpaper.com/static/images/hd-desktop-wallpaper-22.jpg");
  background-size: var(--width) var(--height);
}
.image__img:first-child {
  left: 0;
  width: 100%;
  background-position: center left;
}
.image__img:last-child {
  right: 0;
  width: calc(100% - var(--x, 50%));
  background-position: center right;
  -webkit-filter: grayscale(100%);
          filter: grayscale(100%);
  -webkit-box-shadow: inset 2px 0 0 #111, -2px 0 0 #111;
          box-shadow: inset 2px 0 0 #111, -2px 0 0 #111;
}