Yahoo Mail supports both plain text and rich text (HTML) email composition. There are benefits and detriments for each method, but if you want to use stylized text and inline images, your email will ...

yep, that's my question. can I just create any .html file with html/css/pictures/links, and insert the code into an email using an email client (in my case, Apple's Mail.app on MacOS X Tiger 10.4), ...