By using Preview’s Grab utility, you can easily make screenshots of your Mac desktop and application windows. While you can use various keyboard shortcuts to take screenshots, it is sometimes easier to use mouseclicks instead of the keyboard. Another advantage is that Preview gives you the option of taking timed screenshots that allow you 10 seconds to set up your shot before it snaps the screenshot.
1. Open Preview.
2. Go to the menu, click File, mouseover Grab and select one of the three options:
Selection – this option produces a crosshair cursor for you to click and drag around the area to be included in the screenshot.
Window – a camera cursor appears. Move the camera to the window that you want captured and left-click the mouse.
Timed Screen – you will be given 10 seconds before the screenshot is taken. This is helpful when trying to capture menus and submenus.