.partner-row {
    display:block;
}

.partner-row a {
    display: inline-block;
    max-width: 45%;
    vertical-align: middle;
    padding: 0 2%;
    text-align: center;
}

.partner-row a img {
    width: auto;
    max-width: 100%;
    max-height: 400px;
}