Trying to follow the instructions here, I'd like to be able to insert my picture in the 'From:' header field, but I'm at a loss.
The field you want is "X-Image-Url" rather than "From". Not all email client support viewing it, though. To insert this header, you'll need to check your Mail User Agent (i.e. Thunderbird, Evolution, mutt, etc) documentation. Then once you have an image available online somewhere, you can refer to it like this when you add the
Something like this in your ~/.gnus should do the trick:
(It might be easier to use posting styles to do so.)
I don't think that Gnus supports showing images from X-Image-Url: headers yet, though.
Until it does, you can have it display the header (and click the link) by doing something like: