Add Image To Freemarker Template For Mail?

Im using spring email with freemarker template engine to send email to customers. As part of the signature I would like to add an image, but can't seem to get the template to find

Solution 1:

You can't use relative image URLs in an HTML email - there's nothing for them to be relative to. You need to change your template to use a fully-qualified URL.

You can also, I believe, embed image data within the email, but that's a whole different question.