* {box-sizing: border-box;}

.product_image_container {
  position: relative;
  margin:2% auto;
}

.product_image_container:hover .overlay {
  opacity: 1;
}

/*.product_image_container_a {
  position: relative;
  margin:0 auto;
}

.product_image_container_a:hover .overlay {
  opacity: 1;
}

.product_image_container_b {
  display: inline-block;
  position: relative;
  margin:0 auto;
  width: 49%;
}

.product_image_container_b:hover .overlay {
  opacity: 1;
}*/

.image {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid #eeeeee;
    padding: 10px 5px;
    
}

.overlay {
  position: absolute; 
  bottom: 0; 
  background: rgb(0, 0, 0);
  background: rgba(0, 0, 0, 0.5); /* Black see-through */
  color: #f1f1f1; 
  width: 100%;
  transition: .5s ease;
  opacity:0;
  color: white;
  font-size: 20px;
  padding: 20px;
  text-align: center;
}