How to add logo to e-mail templates?
If you want to add a logo to your e-mail templates, please proceed as follows:
Go to Dashboard > Settings > WP Better Emails > Add Media (you can either upload a new file or choose between the existing ones) > the shortcode %blog_name% can be deleted or kept (if you want your site's name to be displayed when sending an e-mail).
After uploading the file, you can resize the logo as you wish and see a 'Live preview'.
Also, you can send an e-mail preview after saving the changes as presented below: