odoo/addons/share/static/src/css/share.css

.openerp li.oe-share {
    background: url(../img/share.png) no-repeat 0 60%;
    padding-left: 20px;
}

.openerp a.oe-share {
    background: url(../img/share.png) no-repeat center center;
    display: block;
    float: left;
    width: 20px;
    height: 20px;
    margin-top: 3px;
}