img.grayscale {
    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"); /* Firefox 10+ */
    filter: gray; /* IE6-9 */
    -webkit-filter: grayscale(100%); /* Chrome 19+ & Safari 6+ */
    -webkit-transition: all .6s ease; /* Fade to color for Chrome and Safari */
    -webkit-backface-visibility: hidden; /* Fix for transition flickering */
}

img.grayscale:hover {
    filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'matrix\' values=\'1 0 0 0 0, 0 1 0 0 0, 0 0 1 0 0, 0 0 0 1 0\'/></filter></svg>#grayscale");
    -webkit-filter: grayscale(0%);
}

svg {
    /*background: url(http://4.bp.blogspot.com/-IzPWLqY4gJ0/T01CPzNb1KI/AAAAAAAACgA/_8uyj68QhFE/s400/a2cf7051-5952-4b39-aca3-4481976cb242.jpg);*/
}

svg image {
    transition: all .6s ease;
}

svg image:hover {
    opacity: 0;
}

img.half-grayscale {
    filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'saturate\' values=\'0.5\'/></filter></svg>#grayscale"); /* Firefox 10+ */
    filter: gray alpha(opacity=50); /* IE6-9 */
    -webkit-filter: grayscale(50%); /* Chrome 19+ & Safari 6+ */
    -webkit-transition: all .6s ease; /* Fade to color for Chrome and Safari */
    -webkit-backface-visibility: hidden; /* Fix for transition flickering */
}

img.half-grayscale:hover {
    filter: none;
    -webkit-filter: grayscale(0%);
}