.img-container {
  margin: 20px;
  text-align: center;
} 

.img-container img {
   height: auto;

  
   cursor: pointer;
   -webkit-tap-highlight-color: transparent;
   transition: .3s;
  -webkit-transition: .3s;
  -moz-transition: .3s;
   
}
.img-container img:hover{
  transform: scale(0.97);
 -webkit-transform: scale(0.97);
 -moz-transform: scale(0.97);
 -o-transform: scale(0.97);
  opacity: 0.75;
 -webkit-opacity: 0.75;
 -moz-opacity: 0.75;
  transition: .3s;
 -webkit-transition: .3s;
 -moz-transition: .3s;
}