Well I searched and found something about inlined content.

From what I see, all is correct:

,----[ C-h v mm-inlined-types RET ]
| mm-inlined-types's value is 
| ("application/msword" "image/.*" "text/.*" "message/delivery-status" "message/rfc822" "message/partial" "message/external-body" "application/emacs-lisp" "application/x-emacs-lisp" "application/pgp-signature" "application/x-pkcs7-signature" "application/pkcs7-signature" "application/x-pkcs7-mime" "application/pkcs7-mime")
| 
| 
| List of media types that are to be displayed inline.
| See also `mm-inline-media-tests', which says how to display a media
| type inline.
| 
| You can customize this variable.
| 
| Defined in `mm-decode'.
| 
| [back]
`----

and 

,----[ C-h v mm-inline-media-tests RET ]
| mm-inline-media-tests's value is shown below.
| 
| Alist of media types/tests saying whether types can be displayed inline.
| 
| You can customize this variable.
| 
| Defined in `mm-decode'.
| 
| Value:
| (("application/msword"
|   (lambda
|     (handle)
|     (mm-inline-render-with-stdin handle nil "antiword" "-"))
|   identity)
|  ("image/p?jpeg" mm-inline-image
|   (lambda
|     (handle)
|     (mm-valid-and-fit-image-p 'jpeg handle)))
|  ("image/png" mm-inline-image
|   (lambda
|     (handle)
|     (mm-valid-and-fit-image-p 'png handle)))
|  ("image/gif" mm-inline-image
|   (lambda
|     (handle)
|     (mm-valid-and-fit-image-p 'gif handle)))
|  ("image/tiff" mm-inline-image
|   (lambda
|     (handle)
|     (mm-valid-and-fit-image-p 'tiff handle)))
|  ("image/xbm" mm-inline-image
|   (lambda
|     (handle)
|     (mm-valid-and-fit-image-p 'xbm handle)))
|  ("image/x-xbitmap" mm-inline-image
|   (lambda
|     (handle)
|     (mm-valid-and-fit-image-p 'xbm handle)))
|  ("image/xpm" mm-inline-image
|   (lambda
|     (handle)
|     (mm-valid-and-fit-image-p 'xpm handle)))
|  ("image/x-xpixmap" mm-inline-image
|   (lambda
|     (handle)
|     (mm-valid-and-fit-image-p 'xpm handle)))
|  ("image/bmp" mm-inline-image
|   (lambda
|     (handle)
|     (mm-valid-and-fit-image-p 'bmp handle)))
|  ("image/x-portable-bitmap" mm-inline-image
|   (lambda
|     (handle)
|     (mm-valid-and-fit-image-p 'pbm handle)))
|  ("text/plain" mm-inline-text identity)
|  ("text/enriched" mm-inline-text identity)
|  ("text/richtext" mm-inline-text identity)
|  ("text/x-patch" mm-display-patch-inline
|   (lambda
|     (handle)
|     (locate-library "diff-mode")))
|  ("application/emacs-lisp" mm-display-elisp-inline identity)
|  ("application/x-emacs-lisp" mm-display-elisp-inline identity)
|  ("text/dns" mm-display-dns-inline identity)
|  ("text/html" mm-inline-text-html
|   (lambda
|     (handle)
|     (or mm-inline-text-html-renderer mm-text-html-renderer)))
|  ("text/x-vcard" mm-inline-text-vcard
|   (lambda
|     (handle)
|     (or
|      (featurep 'vcard)
|      (locate-library "vcard"))))
|  ("message/delivery-status" mm-inline-text identity)
|  ("message/rfc822" mm-inline-message identity)
|  ("message/partial" mm-inline-partial identity)
|  ("message/external-body" mm-inline-external-body identity)
|  ("text/.*" mm-inline-text identity)
|  ("audio/wav" mm-inline-audio
|   (lambda
|     (handle)
|     (and
|      (or
|       (featurep 'nas-sound)
|       (featurep 'native-sound))
|      (device-sound-enabled-p))))
|  ("audio/au" mm-inline-audio
|   (lambda
|     (handle)
|     (and
|      (or
|       (featurep 'nas-sound)
|       (featurep 'native-sound))
|      (device-sound-enabled-p))))
|  ("application/pgp-signature" ignore identity)
|  ("application/x-pkcs7-signature" ignore identity)
|  ("application/pkcs7-signature" ignore identity)
|  ("application/x-pkcs7-mime" ignore identity)
|  ("application/pkcs7-mime" ignore identity)
|  ("multipart/alternative" ignore identity)
|  ("multipart/mixed" ignore identity)
|  ("multipart/related" ignore identity)
|  ("audio/.*" ignore ignore)
|  ("image/.*" ignore ignore)
|  (".*" mm-inline-text mm-readable-p))
| 
| [back]
`----

All is ok, isn't it ?

P.S: sorry for this crap
-- 
Hacker Wonderland      Xavier Maillard| "Stand Back! I'm a programmer!"
.0.                 zedek@gnu-rox.orgz|
..0                 (+33) 326 770 221 |   Webmaster, emacsfr.org
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