Can I use the iPod to store photos from a digital camera, not only for JPG files, but also RAW image files such as Canon CRW and CR2 and Nikon NEF?

For readers who are not familiar already with the term "RAW image", it first is noted that it isn't an acronym and doesn't "stand for anything", and then defined by Photo.net as:

The output from each of the original red, green and blue sensitive pixels of the image sensor, after being read out of the array by the array electronics and passing through an analog to digital converter. The readout electronics collect and amplify the sensor data and it's at this point that "ISO" (relative sensor speed) is set.

If readout is done with little amplification, that corresponds to a low ISO (say ISO 100), while if the data is read out with a lot of amplification, that corresponds to a high ISO setting (say ISO 3200).

Canon refers to their "RAW" image files as CRW and CR2, acronyms that both stand for "Canon Raw Format". Nikon calls their standard "NEF", which stands for "Nikon Electronic Format".

As noted briefly in the answer to "How can I transfer photos from my digital camera to my iPod?" elsewhere in the iPod Q&A, you can import RAW image files from a variety of digital cameras, including many from Canon and Nikon, directly to "full size" iPod models starting with the iPod photo (30 GB) and second iPod photo (60 GB) (M9830LL/A), using the Apple iPod Camera Connector (US$29) and ending with the iPod 5th Gen Enhanced line.

The iPod Color Display, iPod U2 Edition (Color), iPod 5th Gen (with Video), iPod U2 Edition 5th Gen, iPod 5th Gen Enhanced, and iPod U2 Edition 5th Gen Enhanced -- also can be used to transfer RAW image files from a digital camera with the iPod Camera Connector. However, RAW files imported directly from a digital camera will not be viewable on the iPod.

For older iPod models with "dock" connectors -- iPod 3rd Gen, iPod 4th Gen (ClickWheel), iPod U2 Edition (4th Gen), and the original iPod photo (40 GB, 60 GB) (M9585LL/A and M9586LL/A, respectively) -- you also can import RAW files from a digital camera using the Belkin iPod Media Reader or Digital Camera Link for iPod, but no photos, regardless of format, are immedately viewable on these iPod models (photos are not viewable at all on models with monochrome displays).

Unfortunately, all iPod models starting with the iPod classic (6th Gen) and iPod touch -- all iPod models released September 5, 2007 and later -- do not support importing photos from cameras at all using the iPod Camera Connector or otherwise. These models only support photos reformatted and imported from a computer using iTunes 7.4 or later. Additionally, you cannot import any photographs directly from a digital camera to any iPod mini, iPod nano, or iPod shuffle models.