I am currently working on centering the banner image as the resolution size decreases, rather than having it pushed to the right. The specific page I am addressing can be found here.
My approach involves utilizing a width of 100%.
<!-- BEGIN TEMPLATE HEADING IMAGE - Full 100% Width // -->
<tr class="heading">
<td align="center" valign="top" id="preview" bgcolor="#FFFFFF" style="background-color:#FFFFFF; padding:0px; border-bottom:1px solid #eeeeee;">
<table cellpadding="0" cellspacing="0" border="0" height="400" width="100%">
<tr>
<td background="https://www.acuity-sports.com/newsletter/images/banner10.jpg" bgcolor="#ffffff" width="100%" height="400" valign="top">
<img editable width="600" src="" style="max-width:600; border:0px; display:block;" mc:edit="header_image" />
<!--[if gte mso 9]>
<v:rect xmlns:v="urn:schemas-microsoft-com:vml" fill="true" stroke="false" style="width:600px;height:350px;">
<v:fill type="tile" src="images/main_image.jpg" color="#ffffff" />
<v:textbox inset="0,0,0,0">
<![endif]-->
<!--[if gte mso 9]>
</v:textbox>
</v:rect>
<![endif]-->
</td>
</tr>
</table>
</td>
</tr>
<!-- END TEMPLATE HEADING IMAGE - Full 100% Width // -->