On my 5DmkII, when I first got it, I shot some images with a smaller size raw file.
It seems to do some processing, including demosaicing (and some other raw features, such as setting the black point, and I think some other transforms for the highlights and such too). I’ve seen something like this in some of my own files.
The format is called “sRAW” or “mRAW” in Canon cameras. (And I think other manufacturers have something similar these days too.)
In the case of mine, it looks like this:
If you run the command “exiftool” on the file and lok for “sRAW” (or “mRAW”, depending on your settings), I bet you’d probably see something similar.
Bad news: It’s a (bad) tradeoff between file size and quality. The images are forever stuck somewhere in-between fully-baked JPEGs and “unbaked” raw files.
Good news: They’re higher quality than JPEGs and there are still a bunch of settings you can adjust that just isn’t possible with JPEGs, such as white balance. They’re still somewhat raw-ish. You can still get good results processing the files.
(The one in my screenshot was extremely underexposed and Canon cameras seem to shift underexposed, dark parts of pictures into green sometimes, so it shouldn’t be fully representative of sRAW/mRAW.)
Suggestion for the future: If you’re currently shooting with a reduced small or medium raw file format, I strongly suggest switching to full raw. It’s a bit larger in file size, but definitely worth it for the quality.
(Aside about using any format other than the full, native camera raw: I’m happy I didn’t shoot too many photos with sRAW. I also did convert too many to DNG, but that’s another story… at least converted DNGs are usually—but not always—closer to what the camera gave in its native raw format.)