Centering images within columns

I’m so close to finishing my website and having it ready to launch! Thanks for all the help so far. One final question…

I’ve created five columns on the front page of my site (https://www.clipnyc.com) with one square image each in 3 wide columns, and one grey line image each in 2 narrow columns. The square images keep appearing on the lefthand side of their columns – how do I get the images to center?

My code is below:

<h2 style="text-align: center;">CLIP: The Collegiate Leadership Internship Program</h2>
<h4 style="text-align: center;">A competitive, paid summer internship experience for Jewish  undergraduates in New York City</h4>
<p style="text-align: center;"><span style="color: #ffffff;">.</span></p>
<p style="text-align: center;">[column width="29%" padding="2%"]</p>

<div id="wrap" onclick="window.location.href='https://www.clipnyc.com/?page_id=206'" onmouseover=" this.style.cursor='pointer';"><a id="LearnMore" href="https://www.clipnyc.com/?page_id=206"><strong><span style="color: #000000;">
<h3 style="text-align: center;"><br/><br/><br/>&nbsp;Learn more about CLIP!</h3>
</span></strong></a>

</div>
<p style="text-align: center;">[/column]</p>
<p style="text-align: center;">[column  width="3%" padding="1%"]</p>
<p style="text-align: center;"><img class="aligncenter size-full wp-image-380" title="divider" src="https://www.clipnyc.com/wp-content/uploads/2010/06/divider.gif" alt="" width="33" height="118" /></p>
<p style="text-align: center;">[/column]</p>
<p style="text-align: center;">[column width="29%" padding="1%"]</p>

<div id="wrap" onclick="window.location.href='https://www.clipnyc.com/?page_id=16'" onmouseover=" this.style.cursor='pointer';"><a id="MeetInterns" href="https://www.clipnyc.com/?page_id=16"><strong><span style="color: #000000;">
<h3 style="text-align: center;"><br/><br/>&nbsp;This summer, 41 interns are making an impact on 16 organizations around NYC - <em>Learn More</em></h3>
</span></strong></a>

</div>
<p style="text-align: center;">[/column]</p>
<p style="text-align: center;">[column  width="3%" padding="1%"]</p>
<p style="text-align: center;"><img class="aligncenter size-full wp-image-380" title="divider" src="https://www.clipnyc.com/wp-content/uploads/2010/06/divider.gif" alt="" width="33" height="118" /></p>
<p style="text-align: center;">[/column]</p>
<p style="text-align: center;">[column width="30%" padding="1%"]</p>

<div id="wrap" onclick="window.location.href='https://www.clipnyc.com/?page_id=81'" onmouseover=" this.style.cursor='pointer';"><a id="Alumni" href="https://www.clipnyc.com/?page_id=81"><strong><span style="color: #000000;">
<h3 style="text-align: center;"><br/><br/><br/>&nbsp;Alumni: Learn about how you can stay connected with CLIP!</h3>
</span></strong></a>

</div>
<p style="text-align: center;">[/column]</p>
<p style="text-align: center;">[end_columns]</p>

Thanks!