.img4 {
    height:auto;
    transition: all 0.5s;
    -o-transition: all 0.5s;
    -moz-transition: all 0.5s;
    -webkit-transition: all 0.5s;
}
.img4:hover {
    transition: all 0.3s;
    -o-transition: all 0.3s;
    -moz-transition: all 0.3s;
    -webkit-transition: all 0.3s;
    transform: scale(1.5);
    -moz-transform: scale(1.5);
    -o-transform: scale(1.5);
    -webkit-transform: scale(1.5);
    box-shadow: 0px 0px 0px rgba(0,0,0,0.5);
}