.base {
  width: 100%;
  height: 100%;
  position: relative;
}
.base img {
  display: none;
}

.actual {
  width: 100%;
  height: 100%;
  position: absolute;
  left: 0;
  top: 0;
  transition: 300ms;
  background-position: center;
  background-repeat: no-repeat;
}
.failed {
  composes: actual;
  background-position: center;
  background-size: 40%;
}