Here's something interesting. Here is a photographic comparison of Kim Jong-il, showing changes in his physical appearance (and probably can deduce changes in health conditions).
The photo on the left shows Kim Jong-il visiting a military unit prior to the suspected stroke in 2008. (North) Korean Central News Agency (KCNA) released the photograph on 11 August 2008.
The photo in the center shows Kim attending a meeting with the head of the International Department of Central Communist Party of China Wang Jiarui (not pictured) on 23 January 2009 in Pyongyang, North Korea.
The photo on the right shows Kim attending the 15th anniversary commemoration of Kim Il-sung's death on 08 July 2009.
The photographs above clearly show the difference in Kim's physical appearance before and after the stroke Kim is suspected of suffering sometime between August and September of 2008. The photos also show the clear deterioration in Kim's appearance.Here are some other pictures of Kim before and after the stroke that we were able to find:
Before:
After:
