How to capture a picture of your computer screen

=== by Bob Sutherland ===

This is a lesson on how to use computer software to take a screenshot picture of what is being displayed on your computer screen. There are instructions for four different programs that are each capable of capturing screenshots.

So far I have created beginner lessons on how to use seven different photo editing programs. In each lesson I taught you:

I then created lessons to teach you how to draw shapes or type text on photographs using three photo editing programs. While only some photo editing programs are capable of drawing shapes or typing text on photographs there are other graphics programs that can be used instead. Any programs that I have used always had the same tools and were very similar to the programs in my lessons.

Now I think it is time to teach you how to take a photograph of your computer screen display. A photograph of what is being display by your screen is called a screenshot. Computer software is used to grab or capture the image that is being displayed by your screen and save it as a file.

Once you know how to do a screenshot you can start creating your own lessons. Hopefully I will then be able to slide back into retirement as my services should no longer be required. I wonder, is there any chance I might pick up a camera and try to remember how to use it? I may have joined a community photography club but I cannot remember the last time I lazily loitered around annoying the squirrels by taking their photographs.

The early versions of the Microsoft Windows operating system and the Apple Macintosh operating system both had a very similar way to take a screenshot of your computer screen. It involved pressing down on a specific combination of keys on your computer keyboard all at once. One combination of keys would take a screenshot of your entire screen while a different combination of keys would take a screenshot of the active window that was open on your screen.

The Preview application is installed with the macOS operating system on Macintosh computers. You can use the Preview application to take a screenshot. In the Preview menu across the top of the screen open the File menu. The menu item Take Screenshot will open a submenu with three options.

The first option "From Selection" allows you to draw a selection rectangle by holding your mouse button down as you move your mouse in a diagonal line across the screen. Everything inside the selection box will be captured in a screenshot.

The second option "From Window" will allow you to pick a window that is open on your screen. A screenshot will be taken of the window and its visible contents.

The third option "From Entire Screen" takes a screenshot of everything on the screen of your computer. If you have a very large screen on a desktop computer you may want to change its display settings to a smaller pixel dimensions before taking the screenshot.

Here I have opened the Display window inside System Preferences on my Macintosh computer to change the screen dimensions from 1920 x 1080 pixels down to 1280 x 720 pixels before taking a screenshot.

The yellow rectangle is what a selection box looks like in many programs. The outline of the selection box is usually a thin, dotted, grey line rather than this fat, yellow line.

Inside the selection box is a window. This happens to be a screenshot image that I created of the window. The real window is hidden behind the screenshot image.

In the Preview application menu you have to open the File menu and use Save or Export to save any screenshots you create. This can be a tricky task if you create a screenshot of the entire screen as the screenshot image will fill the screen covering up the menus behind it.

You can use the XnView MP application to take screenshots. This is a screenshot of the XnView MP application running on a Macintosh computer. To take a screenshot go up to the XnView menu across the top of the screen and select Capture in the Tools menu.
Here is the control panel you will see for taking screenshots with XnView MP. You can take a picture of the "Desktop" which means the entire screen or you can take a picture of a "Rectangle" which means the contents of a selection rectangle that you will draw on the screen.

You can set a Delay timer which will give you a few seconds to make adjustments to what is being displayed on your screen before the screenshot happens. In almost all of my screenshots for my lessons I have needed a timer delay of about 10 seconds. That brief time was needed to change which application's menu was being displayed across the top of my screen and then open a menu such as the File menu that I wanted to capture in the screenshot.

The Hotkey setting in the control panel allows you to return to the old way of doing screenshots. You get the opportunity to select from a list a combination of keys on your keyboard that when pressed down together will take a screenshot.

After you take a screenshot with XnView MP it will be displayed on your screen. Here I have taken a screenshot of my desktop. The resulting screenshot is being displayed at 66% of its size which is in contrast to Preview which displays its screenshots at about 100% of their size.

In XnView MP I have to open the File menu across the top of the screen and choose Save As or Export to save my screenshots.

You do not need to use a separate application such as Preview or XnView MP to take screenshots. The macOS operating system has a built in utility for taking screenshots. I fully expect that Linux and Microsoft Windows operating systems also have built in utilities for taking screenshots because I have used them in prior years.

On a Macintosh computer with the Finder menu displayed across the top of the screen open the Go menu and select Utilities.

In the Utilities folder you will either find the Grab application or the Screenshot application. Here is a picture of the Grab application icon that you will want to mouse click or double mouse click on to open.
In the Grab application menu across the top of the screen open the Capture menu. You have four choices.
  1. Selection will allow you to draw a selection rectangle on your screen to define the area that you want to capture in a screenshot.
  2. Window will allow you to select a window on your screen. The window and all of its visible content (but not anything that is scrolled out of sight) will be captured in a screenshot.
  3. Screen will perform a screenshot of the entire computer screen.
  4. Timed Screen will perform a screenshot of the entire computer screen after a ten second countdown timer delay.
Grab will display your screenshot image at near 100% size on your screen. For a screenshot of the entire screen it can then be tricky to try to find your way past the image to access the menus. In the Grab menu across the top of the screen open the File menu and select Save. You will then see a standard Macintosh save window with a choice of PNG, JPEG or TIFF file types.
If you do not find the Grab application in the Utilities folder then you should find the Screenshot application. Here is what it looks like. Mouse click or double mouse click on the Screenshot application to open it.
The Screenshot application is a new application that has replaced the Grab application in the most recent versions of the Macintosh macOS operating system. Instead of using the menus across the top of the screen it just has this row of graphic icons that appear in the lower region of the screen.

The Screenshot icon will automatically appear in the Dock with the application's name beside it to indicate that the program is running.

From left to right here is what each of the graphic icons mean:

  1. The tiny black circle with the white cross represents Cancel screenshot;
  2. Capture entire screen;
  3. Capture selected window;
  4. Capture selected portion of the screen (i.e. selection rectangle);
  5. Video Record entire screen;
  6. Video Record selected portion of the screen (i.e. selection rectangle);
  7. Options:
    • Select save folder (Your screenshot will be automatically saved to this folder on your computer.)
    • Select timer - (You are given a choice of none, 5 seconds or 10 seconds.)
    • Show / Hide mouse cursor - (By default most programs will hide the mouse cursor when taking a screenshot but some programs give you the option to capture it in the image of your screen.)
  8. Start timer countdown

A general rule of thumb is that a program being used to take a screenshot will not capture an image of itself. By this I mean that when you use one of the above programs to take a screenshot all of the menus, icons, selection rectangles and windows needed to take the screenshot are suppose to disappear at the last possible moment so a picture can be taken of what is behind them on the screen.

To take the above screenshots was a coordination challenge as I had to use program A to take a screenshot of program B while program B was in the midst of taking its own screenshot. Your task of just using one program to take screenshots should be a lot easier.