The EOS 30D can record each image as either a RAW image, JPEG image, or both simultaneously.
Like a digital negative, RAW images contain all the unprocessed data from the camera’s sensor. Recorded at 12 bits per pixel, RAW images provide the maximum post processing flexibility. For RAW image handling, Digital Photo Professional software is
JPEG images have compression and Picture Style processing applied and are designed to be more usable straight out of the camera. Depending on the desired image size, different levels of compression (Fine or Normal) can be applied.