<style type="text/css">
 /*=== ???????????????? ================================= */
.slide {
  position   : relative;
  overflow   : hidden;
                    /* ?????????????????????????????????? */
  width      : 500px;
  height     : 500px;
  margin     : auto;      /* ???????????????????????????? */
  background : #fff;
}
 
 /*=== ?????????? ======================================= */
.slide img {
  display    : block;
  position   : absolute;
                      /* ???????????????????????????????? */
  width      : inherit;
  height     : inherit;
  opacity    : 0;
  animation  : slideAnime 8s ease infinite;
}
 
 /*=== ???????????????????????????????????????? ========= */
.slide img:nth-of-type(1) { animation-delay: 0s }
.slide img:nth-of-type(2) { animation-delay: 2s }
.slide img:nth-of-type(3) { animation-delay: 4s }
.slide img:nth-of-type(4) { animation-delay: 6s }
 
 /*=== ???????????????????????? ========================= */
@keyframes slideAnime{
   0% { opacity: 0 }
   3% { opacity: 1 }
  25% { opacity: 1 }
  28% { opacity: 0 }
 100% { opacity: 0 }
}
</style>