Well, well. I feel like a horse's ass. A few years ago I bought a Canon D30. My G3 had committed seppuku a few months previous, and that left me with a Linux box as a workstation for image manipulation. Much to my chagrin (but not surprise), there were no utilities available for Linux for manipulating RAW (lossless) camera images. I was forced to use the camera's JPEG compression, and I've never really been satisfied with the image quality.
Fast-forward 3 years. I'm still shooting JPEG, and I'm still futzing with the images a lot trying to improve the image quality, never being satisfied with them. Matt (who I learned has the same camera I have) and I were recently talking and he told me that there ARE free RAW file manipulators available for Linux, and specifically pointed me at dcraw, which has existed in one form or another since I started looking (though it didn't handle my camera until after my last search.)
So now I'm itching to try it out. Unfortunately, my camera's still in Chicago (so Yoj could take pictures of paintings).
To make matters worse (or more embarrassing) Matt also talked about EXIF information, which only rang a small bell. I wasn't aware that my camera supported it. D'OH! Fortunately for me, although GIMP (somewhat understandably) obliterates this information when it saves an image, ImageMagick's mogrify keeps it. I'm lucky that I'm a programmer, and would rather automate a solution to a problem (In this case, rotating a bunch of images back to portrait mode as they were shot)
Recently, Arshad showed me Gallery. I'm intrigued, since it uses some of the EXIF data. In general, it seems a LOT more interesting than my current solution (not the least of which because the author never responded to my patch, which makes me wonder if he's still working on it)
It's all very humbling. And yet, exciting!