In order to embed HTML, you actually need to copy the rendered HTML from either an existing web page or WYSIWYG HTML editor and then paste it into Gmail.

How to Embed a JPG or GIF in MHTML. HTML files may contain links to images stored in the same folder or externally. MHTML files, on the other hand, embed images within the page itself. By storing ...

The purpose of embedding content is to keeps reader on your site, make the experience better for the reader, and ideally, to gain more loyal readers. Rather than sending your site visitors off to ...