A mobile terminal comprising: a first camera; a touchscreen; and a controller configured to: cause the touchscreen to display a running screen of a message transceiving application, wherein a preview popup window is displayed on a first region of the touchscreen and a first preview image of the first camera is displayed in the preview popup window, characterized in that the controller is further configured to: in response to a user input for a size change of the preview popup window, cause the touchscreen to display in the preview popup window a first portion of a whole camera image received through the camera, the first portion of the whole camera image being selected based on the changed size of the preview popup window, wherein the user input comprises a drag touch input applied to the preview popup window and the first portion of the whole camera image corresponds to the changed size of the preview popup window; and in response to an attachment command, photograph the first portion of the whole camera image and attach the photographed image to the message transceiving application, wherein a data size of the photographed image is based on the size of the preview popup window. a first camera; a touchscreen; and a controller configured to: cause the touchscreen to display a running screen of a message transceiving application, wherein a preview popup window is displayed on a first region of the touchscreen and a first preview image of the first camera is displayed in the preview popup window, cause the touchscreen to display a running screen of a message transceiving application, wherein a preview popup window is displayed on a first region of the touchscreen and a first preview image of the first camera is displayed in the preview popup window, characterized in that the controller is further configured to: in response to a user input for a size change of the preview popup window, cause the touchscreen to display in the preview popup window a first portion of a whole camera image received through the camera, the first portion of the whole camera image being selected based on the changed size of the preview popup window, wherein the user input comprises a drag touch input applied to the preview popup window and the first portion of the whole camera image corresponds to the changed size of the preview popup window; and in response to an attachment command, photograph the first portion of the whole camera image and attach the photographed image to the message transceiving application, in response to a user input for a size change of the preview popup window, cause the touchscreen to display in the preview popup window a first portion of a whole camera image received through the camera, the first portion of the whole camera image being selected based on the changed size of the preview popup window, wherein the user input comprises a drag touch input applied to the preview popup window and the first portion of the whole camera image corresponds to the changed size of the preview popup window; and in response to an attachment command, photograph the first portion of the whole camera image and attach the photographed image to the message transceiving application, wherein a data size of the photographed image is based on the size of the preview popup window.