HTML editing for emails.

I was disappointed with all the free email clients when it comes to adding html code in between the email. Yes, they have the simple ways to add bold, italics etc but what I want is to have html code added in the middle of email and the result should be just what it would be if I had inserted that html on my website. For example, here I am inserting html code to point to an add banner. And you could see the image, and if you click it will take you to the destination.

But if I want to do the same through an email, it doesnt seem like a possibility. First, most of the email clients dont allow inserting html (google doesnt). I found thunderbird does that. So I inserted html and from Thunderbird it shows the image etc as long as you are in the composer. Once the code is sent out to google mail, the image is gone when you receive the mail. I guess this was expected, but I am disappointed. How do we compose emails and make them behave just like a website? Is it a possibility?