For those who like to use their own photos in a desktop-background slide show, Windows offers several ways to display those images.
I suspect most people select the default Fill option, which typically expanses and crops images to fill the entire desktop. (Depending on the aspect ratios of your images, the Stretch option might distort them.)
But as a long-time photographer, I’ve already cropped my images the way I want to see them, and that’s how I’d like to have them displayed as desktop backgrounds. Selecting Center does that, but it puts a distracting black border around the image.
My preference was a nice neutral-gray border, but Windows doesn’t offer that option in its standard settings. Fortunately, after a bit of online searching, I found a way.
It starts with creating and naming your own Windows theme. Set up your background slideshow in the Themes section, select Center for the fit, and click the Save theme link. (For more information on setting up slideshows in Win10, see a Windows Central article.) That theme is saved in a file typically located in C:\Users\[user name]\AppData\Local\Microsoft\Windows\Themes (You’ll probably have to unhide the AppData folder.)
Open the theme file in Notepad or some other text editor. Add the following below the section “[Control Panel\Cursors]” (see Figure 1):
If that control option already exists, simply give it a different set of RGB-color numbers. (I wanted gray, but you can, of course, select any color you like.)