.greyImg {
  filter: gray; /* IE6-9 */
  -webkit-filter: grayscale(1); /* Google Chrome, Safari 6+ & Opera 15+ */
    -webkit-box-shadow: 0px 2px 6px 2px rgba(0,0,0,0.75);
    -moz-box-shadow: 0px 2px 6px 2px rgba(0,0,0,0.75);
    box-shadow: 0px 2px 6px 2px rgba(0,0,0,0.75);
    margin-bottom:20px;
}

.greyImg:hover {
  filter: none; /* IE6-9 */
  -webkit-filter: grayscale(0); /* Google Chrome, Safari 6+ & Opera 15+ */
 
}