.b1t-lazyload[data-src] {
    opacity:0
}

.b1t-lazyload {
    opacity: 1;
    
     transition: opacity 0.3s ease-out;
    -webkit-transition: opacity 0.3s ease-out;
    -moz-transition: opacity 0.3s ease-out;
    -o-transition: opacity 0.3s ease-out;
}