Yes it is possible to create a gif animation to use in our html editor for an email campaign.  However when testing the email in different email clients you will find that not every email client supports animated GIFs.

Newer versions of Outlook (2007, 2010 and 2013) won’t show the animation. Instead, they will show the first frame of the animation. So if you sent yourself a test email in outlook 2007-2013 it would not work.   However if you sent a test email via gmail it would.

To overcome this, many email designers ensure that vital information—perhaps a call-to-action, offer, or headline—is included in the first frame of the GIF. Windows Phone 7 also lacks support for animated GIFs.

Below is a list of email providers who do or do not support GIF animation: