WebStore, How to take a screenshot.
How do I take a screenshot?
In Windows, use the Snipping Tool or Snip & Sketch app located in the All Programs, Accessories folder. Click the new button, draw a box around the image you want to capture and then save it.
On Macintosh, simply press Command-Shift-3 and the screenshot will be saved to your desktop. Or you can use the program called Grab which you will find in the Utilities folder.