Android lock screen?

I have a Huawei P8 Lite 2017 and every now and then it happens that my spear screen background is set to a standard background without me doing anything. At the same time I get one, I always get a new folder in my gallery called Magazine, with pictures in which the standard picture on the spear screen is included. Why does my phone change this background by itself and how can I turn it off or quit?

Once you're on your lock screen, you'll need to drag this control up and down, then click on the circle with the two dashes in the top left corner.

Thank you very much, that helped me a lot.

With pleasure