1. An avatar service system for providing an avatar in a service provided in a mobile environment, the system comprising: a request receiving unit configured to receive a request for an avatar to perform an action; an image data selecting unit configured to select image data and metadata for body layers forming a body of the avatar from a database, in response to the request, and based on the selected body image data configured to further select image data and metadata for item layers disposed on the body of the avatar from the database; and an avatar action processing unit configured to generate action data to apply the action to the avatar based on the selected image data and metadata.