Creating HTML e-mail templates that render the same on every e-mail client, isn't an easy job.  Especially Outlook 2007 makes it really hard to obtain the same goal. For example, using a repeating background image isn't supported in Outlook 2007.

Today I came across this very weird problem.  I wanted to have a border around the content of the mail.  Adding the border was no problem, but when I sent out a test mail, there was a white space between the content and the border of 1px in Outlook 2007.

After some testing and trying stuff, I found a working solution.  Just add the following css to the e-mail template, and the white space 1px is gone!

table td {
    border-collapse: collapse;
}