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