Screenshots in Mac OS X

• Cmd-Shift-3 - - - takes a screenshot of the screen, and saves it as a PNG file on the desktop
  
• Cmd-Shift-4 - - - then select an area: Takes a screenshot of the area & saves it as a PNG file on the desktop
• Cmd-Shift-4 - - - then Space. Click inside an open window: Takes a screenshot of a window & saves it to desktop
• Cmd-Ctrl-Shift-3 - - - Takes a screenshot of the screen, & saves it to the clipboard
• Cmd-Ctrl-Shift-4 - - - then select an area: Takes a screenshot of the selected area & saves it to the clipboard
• Cmd-Ctrl-Shift-4 - - - then Space, then click a window: Takes a screenshot of a window & save it to the clipboard.

To cancel screenshot, click ESC.

In Leopard and later, the following keys can be held down while selecting an area (via Cmd-Shift-4 or Cmd-Ctrl-Shift-4):

• Space - - - to lock the size of the selected region & instead move it when the mouse moves
• Shift - - - to resize only one edge of the selected region.
• Option - - - to resize the selected region with its center as the anchor point