To edit a RAW image you will need either Canons DPP or Photoshop.
1. Create a folder similar to your image name, i.e IMAGE_3390
2. Copy the .CR2 file to be edited into this new folder.
3. Right click the .CR2 file in the IMAGE_3390 folder and select
open with photoshop or start up photoshop and open the file
IMAGE_3390.CR2.
4. Carry out your adjustments, ie exposure, white balance,
sharpening, etc..
5. Now save the file as a .dng file to the IMAGE_3390 folder.
6. Open the .dng file in the photoshop main window.
7. Carry out any further adjustments necessary.
8. Now save the image as a .jpeg to the IMAGE_3390 folder.
9. You should now have three files within the IMAGE_3390 folder,
a .CR2 file a .dng file and a .jpeg file.