GIFs are supported in our editor. They work the same as uploading a normal image to the media library and inserting it into your content.
We recommend the file size not exceed 50 KB. The email will send fine if the GIF exceeds that file size however it will take a while to load for the contact.
Finally, not every email client supports animated GIFs. Particularly older versions of Outlook (2007, 2010 and 2013) won’t show the animation at all. Instead, they will show the first frame. 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.