.slideshow {
  position: relative;
  overflow: hidden;
}
.images {
  background: url(slideshow.jpg);
  position: absolute;
  left: 0;
  top: 0;
  height: 100%;
  width: 300%;
  animation: slideshow 10s linear infinite;
}
@keyframes slideshow {
  0%    { left: 0; }
  100%  { left: -250%; }
}