Improving faces inserting

[giglio robbo' d'acciaio]

I use the following function in order to insert a random faces:

,----
| (defun random-face-header-insert ()
|   (let* ((faces (directory-files "~/News/xfaces" t "\\.png\\(\\.0\\)?$"))
|        (face (nth (random (length faces)) faces)))
|     (save-excursion  
|       (goto-char (point-min))    
|       (insert "Face: "  (gnus-convert-png-to-face face) "\n")    
|       (when (string-match "0$" face)
|       (insert "Face: "
|               (gnus-convert-png-to-face (replace-match face "0$" "1"))
|               "\n")))))
| 
| (add-hook 'message-send-hook 'random-face-header-insert)
`----

I'd like to improve it testing before sending if a faces header is already
present.
Can you help me? Thanks.
-- 
      Daniele Giglio      Dona i tuoi cicli di clock alla ricerca!
      email in ROT13      http://boinc.berkeley.edu/
      qtvtyvb@vby.vg
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