Inserting a Facebook like on your Newsletter
Inserting a “Like” button implies inserting JavaScript or an iFrame and this isn't possible in emailing.
You can simulate this action by adding the “Like” with a link to your Facebook page, for example.
Ournewsletter templates offer the social network icons.
If you want to insert your own logos, you just have to add their images in 20 x 20 px size, for example, and to add to them a redirect link to your page in the affected network.