.partner_image {
    border: 3px solid #e6e6e6;
    margin-bottom: 30px;
    background: #FFF;
}
.partner_image img {
    margin: 0 auto;
}
.partner_image:hover {
    border: 3px solid #3f8ee7;
    transition: all 0.3s ease;
    -moz-transition: all 0.3s ease;
    -o-transition: all 0.3s ease;
    -webkit-transition: all 0.3s ease;
}