Gmail Append HTML for Chrome
More About Gmail Append HTML
Simply copy the content you wish to add, right click on email form and select Append clipboard as HTML.
1) This extension manipulates the html element inside your email, there's no guarantee of what will work as expected and what won't. Please send an email to yourself before sending to an important contact and check the result. Or even better, send the email to an account outside Gmail and see how it displays.
2) Images still needs to be hosted somewhere.
3) USE INLINE CSS.
4) I've created this extension as a PROOF OF CONCEPT mainly for personal usage, but it was working, so I decided to publish and possibly help someone in need. It lacks testing and unfortunately I don't have the time to work on it right now. Consider its use as is.
Source code can be found on GitHub and contributions are very welcome: