img.ss_left {
    float: left;
    width: 45%;
    max-width: 300px;
    min-width: 150px;
    height: auto;
    max-height: 225px;
    min-height: 100px;
    margin-left: 1em;
    margin-right: 1em;
}

img.ss_right {
    clear: left;
    width: 45%;
    max-width: 300px;
    min-width: 150px;
    height: auto;
    max-height: 225px;
    min-height: 100px;
}