.progressive {
    overflow: hidden;
    position: relative;
    background: #efefef
}

.progressive__img {
    width: 100%;
    height: 100%;
    transform: translateZ(0)
}


.progressive--not-loaded:before {
    content: '';
    filter: blur(30px);
}

.progressive--is-loaded::before {
    content: '';
    filter: blur(20px);
    animation: a .5s both;
}

@keyframes a {
    0% {
        filter: blur(20px)
    }
    to {
        filter: blur(0)
    }
}