A method and apparatus for efficiently transmitting and receiving image data of a drawn sketch using a mobile terminal is disclosed. The method for transmitting data in the mobile terminal includes enabling a data transmission input mode to be selected, and compressing image data up to an allowable text transmission size and transmitting the compressed image data if the data transmission input mode is an image mode. The data may further include time information, and the time information provides a relative time when images are generated. The data may further include an identifier for identifying various transmission modes or reception modes, and malfunction of the system can be prevented by the identifier.