Open the settings, click Lock Screen and Password > Lock Screen, and turn off the automatic picture update switch under WLAN. Under WLAN, the automatic image update switch is visible after the magazine lock screen image update switch is turned on. Only when an effective wireless LAN is connected, the magazine lock screen will be automatically updated.
To cancel magazine lock screen, just change a theme without magazine lock screen in Themes application, and select "Don't keep" in the prompt box of "Keep Magazine Lock Screen" according to the page prompts.