A device comprising: a display; and a processor configured to: display a plurality of windows on the display, the plurality of windows corresponding to a plurality of executed applications respectively; determine one of the plurality of windows as a target window, determine at least a partial area for acquiring a size of an object displayed in the target window, acquire a size of the object included in the determined at least partial area, and determine whether to resize the object and the target window comprising the object, based on comparing the acquired size of the object and a preset reference size; wherein in response to the acquired size of the object being less than the preset reference size, the processor is configured to enlarge a size of the object and the target window, display the enlarged object in the enlarged target window, and reduce in size remaining windows of the plurality of windows and respective objects displayed therein and rearrange the remaining windows of the plurality of windows; and wherein in response to the acquired size of the object being greater than the preset reference, the processor is configured to reduce the size of the object and the target window, display the reduced object in the reduced target window, and enlarge in size the remaining windows of the plurality of windows and the respective objects displayed therein and rearrange the remaining windows of the plurality of windows. a display; and a processor configured to: display a plurality of windows on the display, the plurality of windows corresponding to a plurality of executed applications respectively; determine one of the plurality of windows as a target window, determine at least a partial area for acquiring a size of an object displayed in the target window, acquire a size of the object included in the determined at least partial area, and determine whether to resize the object and the target window comprising the object, based on comparing the acquired size of the object and a preset reference size; display a plurality of windows on the display, the plurality of windows corresponding to a plurality of executed applications respectively; determine one of the plurality of windows as a target window, determine at least a partial area for acquiring a size of an object displayed in the target window, acquire a size of the object included in the determined at least partial area, and determine whether to resize the object and the target window comprising the object, based on comparing the acquired size of the object and a preset reference size; wherein in response to the acquired size of the object being less than the preset reference size, the processor is configured to enlarge a size of the object and the target window, display the enlarged object in the enlarged target window, and reduce in size remaining windows of the plurality of windows and respective objects displayed therein and rearrange the remaining windows of the plurality of windows; and wherein in response to the acquired size of the object being greater than the preset reference, the processor is configured to reduce the size of the object and the target window, display the reduced object in the reduced target window, and enlarge in size the remaining windows of the plurality of windows and the respective objects displayed therein and rearrange the remaining windows of the plurality of windows.