img:hover {
 filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'matrix\' values=\'0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0\'/></filter></svg>#grayscale");
 filter: gray;
 -webkit-filter: grayscale(100%);
 }
 img {
 filter: none;
 -webkit-filter: grayscale(0%);
 transition: all .5s;
 }