If you wish to personalize your Windows 10 experience a bit, changing the background of the Lockscreen is a good first step. To change the background of the lockscreen you can simply go to Settings and then Personalize. We’ll help you trough it.
Change Background of Lockscreen
1. Open Start and click on Settings (or type settings in the searchbox and click on Settings)
2. Then choose Personalization
Set a Slideshow as Background on the Lockscreen
If you wish to have a slideshow on your Lockscreen then choose Slideshow in the dropdown menu
3. Under Background choose Slideshow in the dropdown menu
4. Select the locations where the images for the slideshow are stored
Set an Image as the Lockscreen Background
3. Under Background choose Picture
4. Now click on Browse and find the image you want as background.