Fix the Gmail Whitespace Issue

This summer Gmail introduced changes to the webmail interface that caused some issues for email marketers. This change adversely affects emails by including a horizontal white line between images throughout the email content.

Here is an example of the issue:

The fix is to set the font-size to 0 (zero) on the master table tag. 

<table border="0" cellpadding="0" cellspacing="0" width="650" style="font-size:0;">

<!--
    email body 
-->
</table>

Here is what the email example looks like with the font-size 0 in place:

Alternatively, if you are not using table tags, you can set the img tags to display block.

<img src="http://www.thepiepers.net/image.jpg" height="50" width="50" style="display:block">