Whether you are asking for tech support or trying to show something to your friends, taking a picture of your screen is a very useful tool. Fortunately, Mac OSX natively offers useful tools to do so, allowing you to to take many kinds of screenshots using just key commands. Here are the basics:
- To take a screenshot of your whole screen, hit the key combination Command + Shift + 3. This will save a PNG image of your screen to your desktop, titled Screen Shot <current time>.png
- To take a screenshot of a region of your screen, hit Command + Shift + 4. This will change your cursor to a crosshairs, and if you drag the crosshairs to create a shaded box, it will take a screenshot of that box. (To cancel the screenshot, click without dragging.)
If you hit Command + Shift + 4 and follow it up with the Space key, you will notice that the cursor turns into a camera. Dragging that camera over any open window will highlight the window, and clicking it will generate a screenshot of only that window. This useful if you are trying to troubleshoot only a particular program, for example.
- Finally, to take a timed screenshot, where a countdown appears before the image is generated, open the Grab app located in /Applications/Utilities/Grab and on the top menu bar, go to Capture -> Timed Screen. This app can also be used to access all of the previous options.