.img-left {
    float: left;
    max-width: min(48%, 520px);
    height: auto;
    margin: .35em 1.4em .8em 0;
}
.img-right {
    float: right;
    max-width: min(48%, 520px);
    height: auto;
    margin: .35em 0 .8em 1.4em;
}
.img-shadow { box-shadow: 0 4px 14px rgba(0, 0, 0, .22); }
.img-block { clear: both; margin: 1.2em 0; }
.img-block-left { text-align: left; }
.img-block-center { text-align: center; }
.img-block-right { text-align: right; }
.img-block img { max-width: 100%; height: auto; }
.clear { clear: both; }
@media (max-width: 640px) {
    .img-left,
    .img-right {
        float: none;
        display: block;
        max-width: 100%;
        height: auto;
        margin: 1em auto;
    }
}