.lazy-hidden{
    background:url(images/loading.gif) 50% 50% no-repeat #aad7e7;
    z-index: 8;
}
.lazy-loaded {
    -webkit-transition: opacity 0.3s;
    -moz-transition: opacity 0.3s;
    -ms-transition: opacity 0.3s;
    -o-transition: opacity 0.3s;
    transition: opacity 0.3s;
    opacity: 1;
}