Building HTML Emails

When working on an HTML email template for my company to send out I ran into a little snag. In Gmail, Yahoo!, and a few other email clients, the images didn't look right. Some wouldn't have any gaps or a gap would appear to the left while in another client it would be to the right. After struggling with this for a while, I finally found a solution.

Here is how to remove gaps from around images in Gmail/Yahoo!/etc. HTML emails:

<img src="sample.gif" style="display: block;" />