Which MIME type should be used for a raw image?

Raw images are produced by cameras, scanners, etc. and typically give you more post-processing flexibility than JPEG images.

If I’m serving this kind of file from my web server, which media type (a.k.a. MIME type) should I use? I’m specifically interested in the CR2 files produced by recent Canon cameras, but answers could also address Adobe’s Digital Negative (DNG) format or raw files from other manufacturers’ cameras. (I didn’t see anything relevant in this list from the IANA.)

Solution

According to this XML file from the (defunct?) GNOME RAW Thumbnailer project, the MIME type for raw images in general is image/x-dcraw. Listed by their file extensions, here are the other file types mentioned in that file:

ARW: image/x-sony-arw
CR2: image/x-canon-cr2
CRW: image/x-canon-crw
DCR: image/x-kodak-dcr
DNG: image/x-adobe-dng
ERF: image/x-epson-erf
K25: image/x-kodak-k25
KDC: image/x-kodak-kdc
MRW: image/x-minolta-mrw
NEF: image/x-nikon-nef
ORF: image/x-olympus-orf
PEF: image/x-pentax-pef
RAF: image/x-fuji-raf
RAW: image/x-panasonic-raw
SR2: image/x-sony-sr2
SRF: image/x-sony-srf
X3F: image/x-sigma-x3f