Mime is a standard for waving your hands through the air, aimlessly, while people stand around yawning.
MIME, however, is a standard for encoding your articles, aimlessly, while all newsreaders die of fear.
MIME may specify what character set the article uses, the encoding of the characters, and it also makes it possible to embed pictures and other naughty stuff in innocent-looking articles.
Gnus pushes
MIME articles through
gnus-display-mime-function to display the
MIME parts. This is
gnus-display-mime by default, which creates a bundle
of clickable buttons that can be used to display, save and
manipulate the MIME objects.
The following commands are available when you have placed point over a MIME button:
gnus-article-press-button). If built-in viewers
can not display the object, Gnus resorts to external viewers
in the mailcap files.
If a viewer has the ‘copiousoutput’ specification, the
object is displayed inline.
gnus-mime-view-part).
gnus-mime-view-part-as-type).
gnus-mime-view-part-as-charset).
gnus-mime-save-part).
gnus-mime-save-part-and-strip).
gnus-mime-replace-part).
gnus-mime-delete-part).
gnus-mime-copy-part). If given a
prefix, copy the raw contents without decoding. If given a
numerical prefix, you can do semi-manual charset stuff (see
gnus-summary-show-article-charset-alist in
Paging
the Article). Compressed files like .gz and .bz2 are automatically decompressed if
auto-compression-mode is enabled (see Accessing
Compressed Files).
gnus-mime-print-part). This command respects
the ‘print=’ specifications in the
.mailcap file.
gnus-mime-inline-part) as
‘text/plain’. If given a prefix,
insert the raw contents without decoding. If given a
numerical prefix, you can do semi-manual charset stuff (see
gnus-summary-show-article-charset-alist in
Paging
the Article). Compressed files like .gz and .bz2 are automatically decompressed
depending on jka-compr regardless of
auto-compression-mode (see Accessing
Compressed Files).
gnus-mime-view-part-internally).
gnus-mime-view-part-externally).
gnus-mime-pipe-part).
gnus-mime-action-on-part).Gnus will display some MIME objects automatically. The way Gnus determines which parts to do this with is described in the Emacs MIME manual.
It might be best to just use the toggling functions from the article buffer to avoid getting nasty surprises. (For instance, you enter the group ‘alt.sing-a-long’ and, before you know it, MIME has decoded the sound file in the article and some horrible sing-a-long song comes screaming out your speakers, and you can't find the volume button, because there isn't one, and people are starting to look at you, and you try to stop the program, but you can't, and you can't find the program to control the volume, and everybody else in the room suddenly decides to look at you disdainfully, and you'll feel rather stupid.)
Any similarity to real events and people is purely coincidental. Ahem.
Also see MIME Commands.