Try changing
#fblogo {
display: block;
margin-left: auto;
margin-right: auto;
height: 30px;
}
to
.fblogo {
display: inline-block;
margin-left: auto;
margin-right: auto;
height: 30px;
}
#images{
text-align:center;
}
HTML
<div id="images">
<a href="https://stackoverflow.com/questions/11819417/mailto:[email protected]">
<img class="fblogo" border="0" alt="Mail" src="http://olympiahaacht.be/wp-content/uploads/2012/07/email-icon-e1343123697991.jpg"/></a>
<a href="https://www.facebook.com/OlympiaHaacht" target="_blank">
<img class="fblogo" border="0" alt="Facebook" src="http://olympiahaacht.be/wp-content/uploads/2012/04/FacebookButtonRevised-e1334605872360.jpg"/></a>
</div>
DEMO.