How to Take a Screenshot in Mac OS X
Capture the entire screen
Press Command (⌘) + Shift + 3.
The PNG file thus generated is saved to your desktop.
Capturing a part of the screen
Press Command + Shift + 4. The cursor turns into a crosshair.
Move it at a corner of the area to be captured.
Drag the pointer to select the same area. To adjust the selection, hold down Shift, Option, or down the spacebar as you drag the pointer.
Once the area of your choice selected, release the mouse button or trackpad. To cancel, press Esc before releasing the button.
The PNG file thus generated is saved to your desktop.
Capture a window
Press Command + Shift + 4. The cursor turns into a crosshair.
Press the space bar. The cursor changes to a camera.
Place on a window to put it highlighted.
Make a click with your mouse or your track pad. To cancel, press Esc before clicking.
The PNG file thus generated is saved to your desktop.
Capturing a menu
Click the menu to reveal the contents.
Press Command + Shift + 4. The cursor turns into a crosshair.
Drag the pointer to select the entire menu.
Release the mouse button or track pad. To cancel, press Esc before releasing the button.
The PNG file thus generated is saved to your desktop.
Capturing a menu without its title
Click the menu to reveal the contents.
Press Command + Shift + 4. The cursor turns into a crosshair.
Press the space bar. The cursor changes to a camera.
Place it on the menu to put it highlighted.
Make a click with your mouse or your track pad. To cancel, press Esc before clicking.
The PNG file thus generated is saved to your desktop.
Additional Information
Mac OS X 10.6 and later, the screenshots are saved in PNG format on the desktop and automatically named “Capture time to time PNG”
To save a snapshot in the clipboard, and not on the desktop, press Command + Shift + Control + 4.
You can view using Preview or other applications for editing images.
It is possible that you cannot take a picture of windows of some applications, such as DVD player.