Remove spacing between table rows in HTML email - html

Question

Let me start by saying that I haven't built an HTML email in a long time; I've been spoiled by CSS for far too long, so going back to building things with tables is incredibly frustrating. I am having trouble getting two rows to sit flush against each other; there is a gap that I can't eliminate, no matter what I've tried. Scouring other posts on S.O. only yields solutions I've already tried and that have not worked. About 40% of the intended audience is viewing emails on Outlook, meaning CSS support is incredibly limited. Things I've tried:
border-collapse:collapse (which I already put in place by default from the start)
setting margin: 0 (just about everywhere)
cellspacing and cellpadding to zero (which I already did by default when building the tables).
display:block and display:inline-block (not really supported by Outlook, but didn't solve my problem anyway).
Here are my code snippets (ignore any CSS classes; again there is not yet any embedded CSS, those are just placeholders at this point. Any embedded CSS will primarily be to handle email client-specific issues.)
<!--2 Column Layout : BEGIN-->
<tr>
<td align="center" valign="top" style="text-align: center; padding:0px; border-width:0px; margin:0px;">
<table cellspacing="0" cellpadding="0" border="0" width="100%" style="border-collapse:collapse; border:0px; border-spacing:0px;">
<tr>
<td class="stack-column-center" style="text-align: center; padding:0px; border-width:0px; margin:0px;">
<table cellspacing="0" cellpadding="0" border="0" style="border-collapse:collapse; border:0px; border-spacing:0px;">
<tr>
<td style="text-align: center; padding:0px; border-width:0px; margin:0px;">
<img src="http://i1024.photobucket.com/albums/y303/aadBresco/monkey_wrench_zpstk6rgf3j.png" width="300" alt="Monkey Wrench" border="0" class="fluid">
</td>
</tr>
</table>
</td>
<td class="stack-column-center" style="text-align: center; padding:0px; border-width:0px; margin:0px;">
<table cellspacing="0" cellpadding="0" border="0" style="border-collapse:collapse; border:0px; border-spacing:0px;">
<tr>
<td style="text-align: center; padding:0px; border-width:0px; margin:0px;">
<img src="http://i1024.photobucket.com/albums/y303/aadBresco/auto_parts_zpsf1bs9tgv.png" width="300" alt="Auto Parts" border="0" class="fluid">
</td>
</tr>
</table>
</td>
</tr>
</table>
</td>
</tr>
<!--2 Column Layout : END-->
<!--2nd Hero Image : BEGIN-->
<tr>
<td class="full-width-image">
<img src="http://i1024.photobucket.com/albums/y303/aadBresco/sliced-bread_zpsxt8z6pjt.png" width="600" alt="Sliced Bread" border="0" align="center" style="width: 100%; max-width: 600px; height: auto;">
</td>
</tr>
<!--Hero Image : END-->
The small gap at the bottom of the row is visible if you look closely. It is 4px in height.

Answer 1

I t looks good; not bad. Also, you don't need to add all the css details to each row and column; just add: or or ; and then in your css sheet (If you don't have it then just create on) add td.Whatever-you-decide-to-name-it or tr.Whatever-you-decide-to-name-it or table.Whatever-you-decide-to-name-it.
Hope this helps!!!

Answer 2

Since your img is not containing a width (even auto), initialize it as a block element.Since you have mentioned that block is not supported in your case I added display:table for your img. I added the working snippet with this answer.
img {
display: table;
}
<!--2 Column Layout : BEGIN-->
<tr>
<td align="center" valign="top" style="text-align: center; padding:0px; border-width:0px; margin:0px;">
<table cellspacing="0" cellpadding="0" border="0" width="100%" style="border-collapse:collapse; border:0px; border-spacing:0px;">
<tr>
<td class="stack-column-center" style="text-align: center; padding:0px; border-width:0px; margin:0px;">
<table cellspacing="0" cellpadding="0" border="0" style="border-collapse:collapse; border:0px; border-spacing:0px;">
<tr>
<td style="text-align: center; padding:0px; border-width:0px; margin:0px;">
<img src="http://i1024.photobucket.com/albums/y303/aadBresco/monkey_wrench_zpstk6rgf3j.png" width="300" alt="Monkey Wrench" border="0" class="fluid">
</td>
</tr>
</table>
</td>
<td class="stack-column-center" style="text-align: center; padding:0px; border-width:0px; margin:0px;">
<table cellspacing="0" cellpadding="0" border="0" style="border-collapse:collapse; border:0px; border-spacing:0px;">
<tr>
<td style="text-align: center; padding:0px; border-width:0px; margin:0px;">
<img src="http://i1024.photobucket.com/albums/y303/aadBresco/auto_parts_zpsf1bs9tgv.png" width="300" alt="Auto Parts" border="0" class="fluid">
</td>
</tr>
</table>
</td>
</tr>
</table>
</td>
</tr>
<!--2 Column Layout : END-->
<!--2nd Hero Image : BEGIN-->
<tr>
<td class="full-width-image">
<img src="http://i1024.photobucket.com/albums/y303/aadBresco/sliced-bread_zpsxt8z6pjt.png" width="600" alt="Sliced Bread" border="0" align="center" style="width: 100%; max-width: 600px; height: auto;">
</td>
</tr>
<!--Hero Image : END-->

Answer 3

Since display:block wasn't a solution, I tried removing the <!doctype html> declaration and that fixed the issue. Normally I don't think this would be acceptable, but to the best of my knowledge - and after testing - it does not have any negative impact for HTML email.