to be added in the style.css

style.css

 .teamMemberInner img {
    filter: url('js/filters.svg#grayscale');
    filter: gray;
    -webkit-filter: grayscale(1);
    -webkit-transition: all 0.7s ease;
    -moz-transition: all 0.7s ease;
    -ms-transition: all 0.7s ease;
    -o-transition: all 0.7s ease;
    transition: all 0.7s ease;
}
.teamMemberInner img:hover {
    filter: none;
    -webkit-filter: grayscale(0);
    -webkit-transition: all 0.7s ease;
    -moz-transition: all 0.7s ease;
    -ms-transition: all 0.7s ease;
    -o-transition: all 0.7s ease;
    transition: all 0.7s ease;
}