1. Source of images: The images in Hong Kong 49 Gallery are mainly from 49 hospitals and medical organizations in Hong Kong, which are usually taken with the consent of patients and used for teaching or research purposes. The Hong Kong Atlas, on the other hand, has a much wider range of sources of images, which may include various scenes, buildings, people, historical events, etc. in Hong Kong.
2. Types and themes of images: The Hong Kong 49 gallery focuses on medical and health themes, including various diseases, surgical procedures, and medical equipment. While HK gallery covers a wider range of topics, including social events, historical moments, people's images, and so on.