Hyperlinked images in table won't work

I apologize if this question has been addressed, but I can't find a workable solution. The code is below.

<table style="width:45em">
        <tr>
            <td>
                <a class="section" href="http://www.aoh.com" target="_blank"><img src="graphics/aohnational.png" alt="" ></a>
            </td>
            <td>
                <a class="section" href="http://www.ncaoh.com" target="_blank"><img src="graphics/ncaoh.png" alt=""></a>
            </td>
        </tr>
        <tr>
            <td>
                <a class="section" href="http://ift.tt/12dxfFv" target="_blank"><img src="graphics/logo.jpg" width="275" height="60" alt=""></a>
            </td>
            <td>
                <a class="section" href="http://ift.tt/1HzuCfY" target="_blank"><img src="graphics/spcc.png" alt=""></a>
            </td>
        </tr>
        <tr>
            <td>
                <a class="section" href="http://ift.tt/1HzuCg0" target="_blank"><img src="graphics/spcs.jpg" width="275" height="60" alt=""></a>
            </td>
            <td>
                <a class="section" href="http://ift.tt/1HzuCg4" target="_blank"><img src="graphics/sgcc.png" alt=""></a>
            </td>
        </tr>
        <tr>
            <td>
                <a class="section" href="http://ift.tt/1GvNCxh" target="_blank"><img src="graphics/ulsterproj.png" width="275" height="60" alt=""></a>
            </td>
            <td>
                <a class="section" href="http://ift.tt/1HzuzAV" target="_blank"><img src="graphics/rileyslogo.png" width="275" height="60" alt=""></a>
            </td>
        </tr>
        <tr>
            <td>
                <a class="section" href="http://ift.tt/1GvNFsM" target="_blank"><img src="graphics/gpspd.png" width="275" height="60" alt=""></a>
            </td>
            <td>
                <a class="section" href="http://ift.tt/1GvNCxj" target="_blank"><img src="graphics/wilmpipes.png" width="275" height="60" alt=""></a>
            </td>
        </tr>
            <td>
                <a class="section" href="http://ift.tt/1HzuzRi" target="_blank"><img src="graphics/bannerbar.jpg" width="275" height="60" alt=""></a>
        </td>
    </table>

I am trying to make each image linkable to an exterior website, so that it functions like a typical "Links" page. The bottom image is the only one that stays linked. Can someone please help me?