.photo-box {;
    width:200px;
    height:180px;
    border:1px solid #ccc;
    float:left;
    margin:15px 15px 0 15px;

    -webkit-transition: all 0.3s ease;
    -moz-transition: all 0.3s ease;
    -ms-transition: all 0.3s ease;
    -o-transition: all 0.3s ease;
    transition: all 0.3s ease;
}
.photo-box:hover {
    background:red;

    -webkit-transition: all 0.3s ease;
    -moz-transition: all 0.3s ease;
    -ms-transition: all 0.3s ease;
    -o-transition: all 0.3s ease;
    transition: all 0.3s ease;
}
.photo-box.photo1 {
    background-image: url();
}
.photo-box.photo2 {
    background-image: url();
}
.photo-box.photo3 {
    background-image: url();
}
.photo-box.photo4 {
    background-image: url();
}
.photo-box.photo5 {
    background-image: url();
}
.photo-box.photo6 {
    background-image: url();
}
.photo-box.photo7 {
    background-image: url();
}
.photo-box.photo8 {
    background-image: url();
}
.photo-box.photo9 {
    background-image: url();
}
.photo-box.photo10 {
    background-image: url();
}
.photo-box.photo11 {
    background-image: url();
}
.photo-box.photo12 {
    background-image: url();
}
.photo-box.photo13 {
    background-image: url();
}
.photo-box.photo14 {
    background-image: url();
}
.photo-box.photo15 {
    background-image: url();
}
.photo-box.photo16 {
    background-image: url();
}