.social_tabs ul li.social_icon img {
    max-height: none;
    max-width: none;
    height: 23px;
    width: auto;
    padding: 0 0 0 5px;
}
.social_icon:first-child a img,
.social_icon:nth-child(2n) a img,
.social_icon:nth-child(3n) a img {
    background: none;
    background-size: 23px 23px;
}