.lazyload,
.lazyloading {
    opacity: 0;
}

.lazyloaded {
    opacity: 1;
    transition: opacity 300ms;
}

.lazyload {
    opacity: 0;
}

.lazyloading {
    opacity: 1;
    transition: opacity 300ms;
    background: #f7f7f7 url('../../images/loading.gif') no-repeat center;
}