VML

Vector Markup Language and Backgrounds

Backgrounds might seem like they should be a simple effect to achieve in HTML email, but that’s not always the case. Outlook 2007, 2010 and even 2013 will give users who rely on the body’s background-image property a lot of trouble. Because of these problems many have turned to Vector Markup Language (VML), part of the Office Open XML standards.

Read more about it in this blog.