well,
you can set the header to something else depend on what you want to print.. here is a shortlist
text/plain: Plain text.
text/html : HTML files.
text/richtext: Rich Text Format.
image/gif : GIF images
image/jpeg : JPEG images
image/x-xbitmap X bitmap is a very simple pixel-by-pixel description of images.
audio/basic: Basic 8-bit, ulaw compressed audio files.
audio/x-wav: Microsoft Windows audio format.
video/mpeg: MPEG compressed video.
video/quicktime: Quicktime video.
video/x-msvideo: Microsoft Video. Usually ends with the extension .avi.
application/octet-stream
application/postscript: Postscript files.
I believe there are some more but i don't remember
cheer
kevin