Sending illustrated (Christmas card) emails

A client of ours wants to send all his clients an illustrated email for Christmas (yes, I know, and I know).

I know that email HTML is a very different beast to browser HTML, and there ar开发者_如何学Goe a lot of things to bear in mind, but I don't know the best place to get this kind of information.

Does anyone know of any good sources, or can we get a list of best practices here?

EDIT: What about mail deployment? Is it worth using something like mailchimp? Anyone?

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Joel Spolsky tweeted this link (Blog Post titled ROCK SOLID HTML EMAILS) related to what you are asking. Haven't read it, but I guess it's good.

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Maybe this article helps: How to code HTML email newsletters