Mac OS X offers a number of useful options for taking screenshots—images of your screen, or parts of it—that you can use for how-to guides, for sharing with others, or even for sending to tech support. Here’s a quick look at those options, including some tricks for getting the best screenshots.
The simplest screenshot option is to snap an image of your entire screen. You do this by pressing Shift+Command+3. The resulting image is saved, one for each connected display, to your desktop with the name Screen Shot, followed by the date and time.
If you don’t want the entire screen, press Shift+Command+4. Your cursor changes to a marquee for selecting an area of the screen to capture, with the dimensions of the selected area appearing next to the marquee. Release the cursor button to take the shot.
But what if you want to take a snapshot of a particular object on the screen? Press the shortcut for a selection, Shift+Command+4, but instead of selecting an area, press the Space Bar. The marquee turns into a camera icon that highlights any object or interface element beneath it. Click the mouse button, and the highlighted item—and just that item—is captured in your screenshot.
Here’s a quick look at the screenshot I just took of a Finder window using this trick.
A common issue I have is that I select a screen area, but it’s not quite the area I want. Instead of starting over, just press the spacebar—this lets you move the entire selection. If you let go of the spacebar, you can continue to resize your selection from there.
Mac OS X also offers some options for controlled resizing. Press the screen-selection shortcut and select an area of the screen, but then hold down the Shift key. This lets you resize your selection in a single dimension, horizontally or vertically, without changing the other dimension. If you need to resize in the other dimension, release the Shift key and then press it again to reset the axis lock.
You can also resize a selection rectangle proportionately. Just hold down the Option key, and drag the mouse cursor away from or towards the center of the rectangle. The rectangle retains its height-to-width ratio while resizing.
You can even combine all these special features for resizing and moving your selection in order to get the perfect screenshot framing.
What if you plan to edit your screenshot immediately? It turns out that if you add the _Control_ key to either your fullscreen or selection keyboard shortcut, instead of saving your screenshot as a file on the desktop, OS X copies the image to the clipboard. You can then paste it right into an image editor. Or you can just open OS X’s own Preview app and use the New From Clipboard command.