1. A mail server connected to a mobile terminal through a network, comprising a control unit and a storage unit, wherein: the storage unit stores words and display information associated with the words as a word-image associating dictionary; and the control unit controls the processing of: receiving an ID code of the mobile terminal, character information, text information, and selected expression information from the mobile terminal, dividing the text into unit of a word, synthesizing an animation image of the character by using the display information and the expression information associated with the word, and outputting the animation image to the mobile terminal.