How do I use the FreeForm editor ? Freeform guidelines

You are able to simply cut and paste your own HTML code when creating your email message in the freeform editor. To help ensure the best results, please follow these guidelines:

1. All images must be hosted and referenced by absolute urls in your source code (i.e. <img src='http://www.mysite.com/logo_1.gif'> rather than <img src='/logo_1.gif'>)
2. Your HTML source code file should not exceed 45KB
3. Email width should be around 600px for consistent viewing on most screen resolutions and window sizes
4.  The use of HTML forms in your email message is not recommended; most email clients will not render forms correctly
5.  We recommend sticking to basic HTML and to avoid using scripting (JavaScript, Perl, etc), HTML frames, layering or absolute positioning. While suitable for browsers, most email clients have difficulty rendering or actively ignore these design elements
6. CSS should be embedded in the BODY rather than the HEAD of your document
7. External CSS file references are not recommended. Many email clients will ignore external css references and any CSS in the HEAD section of an HTML email
8. Do not place CSS styles directly in the BODY tag; some webmail clients will ignore body attributes/styles.
9. Background colors should be applied to container tables/divs, rather than the BODY. -Avoid using background images, as some email clients will not display them
10.  Do not rely on CSS inheritance. Write your CSS specifically (i.e. element#idname p {} as opposed to just p {}. Text links need explicit inline styling to render as desired in most webmail clients
11.  Avoid commenting within the code - this could cause issues with webmail clients

Learn more about the Do's & Don't of Html: http://help.verticalresponse.com/how-to/tutorial/the_dos_and_donts_of_email_html/