.container-img-prod {
  position: relative;
  /*width: 50%;*/
}
.overlay {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  height: 100%;
  width: 100%;
  opacity: 0;
  transition: .5s ease;
}
.container-img-prod:hover .overlay {
  opacity: 1;
}