Use this command to close the active window or dialog box.
Double-clicking a Control-menu box is the same as choosing the Close command.
Note: If you have multiple windows open for a single image, the Close command on the image Control menu closes only one window at a time. You can close all windows at once with the Close All command on the Window menu.
Shortcuts
Keys: CTRL+F4 closes a image window
ALT+F4 closes the window or dialog box