Make it simple! You do not need to use all this conditional Outlook code blocks to control email width in desktop view. Check example above.

<table bgcolor="#00a9f7" width="100%" cellpadding="0" cellspacing="0">
<tr>
    <td align="center">
        <!-- width wrapper table -->
        <table bgcolor="#ffffff" align="center" cellpadding="0" cellspacing="0">
        <tr>
            <td width="600" align="center">
                <table align="center" cellpadding="0" cellspacing="0">
                <tr>
                    <td width="600" align="center">
                        <img src="http://placehold.it/600x300" width="600" alt="" border="0" style="width:100%!important;height:auto!important;display:block;"/>
                    </td>
                </tr>
                </table>
                <table width="100%" cellpadding="0" cellspacing="0">
                <tr>
                    <td align="center" style="font-family:Architects Daughter,Georgia,Times New Roman,sans-serif;font-size:21px;color:#505050;mso-line-height-rule:exactly;line-height:25px;padding-top:20px;padding-bottom:20px;padding-left:20px;padding-right:20px;">
                        Gmail App iOS &amp; Android <br/> responsive behavior support
                    </td>
                </tr>
                </table>
            </td>
        </tr>
        </table>
    </td>
</tr>
</table>