Step One: Enable Photo Viewer in the Registry
We’ll need to add the same registry entries that were present on Windows 7 and 8.1, and are still present on systems that upgraded from those old versions of Windows. To make things easy, we’ve put together a Registry hack you can use to make these edits quickly because they’re a little cumbersome to make manually. Download and unzip the following file:
Inside, you’ll find two hacks. Run the “Activate Windows Photo Viewer on Windows 10” hack to create the keys and values in the Registry and activate Photo Viewer. And if you ever want to deactivate it, just run the “Deactivate Windows Photo Viewer on Windows 10 (Default)” hack. Of course, there’s no real need to deactivate it in the Registry. You can always leave it available and just associate your image files with a different app.
Step Two: Set Windows Photo Viewer as Your Default Image Viewer
To associate an image file with Photo Viewer, right-click any type of image file—for example, a .png, .jpg, .gif, or .bmp file—and select Open With > Choose Another App.
In the “How do you want to open this file?” window, select Windows Photo Viewer. If you don’t see it at first, scroll to the bottom of what’s listed and click the “More apps” option—it’ll show up. Select the “Always use this app to open .___ files” option, and then click “OK.”
Windows Photo Viewer will now be the default image viewer for that type of image file. You’ll need to repeat this process for each type of image file you want to use it with. In other words, whenever you open an image that opens in the Photos app, just close the Photos app and use the “Open with” menu to associate that file type with Windows Photo Viewer. You’ll only have to do this the first time you open each new type of image file.