|Underwater photos are usually blue|
The versions of libraw and dcraw currently in the Ubuntu repos have a slight problem. When accessing RAW files from Canon's latest 650D, they display them entirely in pink - which probably isn't what you want.
The problem is simple enough: the versions of dcraw/libraw used by all the RAW processing apps in Ubuntu 12.10 (aside from eog - so Shotwell, UFRaw, RawTherapee, etc.) don't have the 650D listed yet, so the ICC profiles aren't getting properly interpreted.
One solution is to rebuild your applications, such as Shotwell, with the appropriate versions of the underlying raw libraries. That can be a pain, so I took the easier option, and opted to convert the images to JPEG first, thereby circumventing the issue.
sudo apt-get install libjasper-dev libjpeg-dev liblcms1-dev graphicsmagick
gcc -o dcraw -O4 dcraw.c -lm -ljasper -ljpeg -llcms
sudo mv dcraw /usr/local/bin/dcraw
echo alias rawtojpg="\"find . -name '*.CR2' -print0 | xargs -0 -n 1 -P 8 -iIMG gm convert IMG -format jpg IMG.jpg\"" >> ~/.bashrc
|At least it's better than pink|
Update, 8th August 2013
See my comment below for a complete solution to this problem.
Assuming you've already followed the preceding instructions in this post, all you need to do is install gimp-dcraw; then you'll be able to open your 650D CR2s with GIMP:
sudo apt-get install gimp-dcraw