A method of transferring image data from a first terminal to a second terminal connected via a communication network, the method comprising: displaying on a screen of the first terminal a screen image generated by a processor executed application; a processor executing a communication client to: establish a communication event between the first and second terminals and display at the first terminal an interactive selection component; a user at the first terminal actuating the selection component to select at least one object displayed on the screen to be shared with the second terminal, wherein the communication client accesses data defining displayed object dimensions and adjusts the selection component based on those dimensions to cause the at least one object selected by the window selection component to be displayed on a screen of the second terminal by transferring image data over the communication network in the established communication event.