Change Screen Saver / Wallpaper from Endpoint Portal

Login to endpoint.microsoft.com as GA or Intune Admin. Navigate to Devices > Configuration Profiles

Click Edit on Configuration to edit the screen saver. 1. This is for enable the setting to Windows 10 Pro version device. 2. This is the OMA-URI to set the screen saver to the target group.

Click Edit on screen saver and paste the public picture link at Value * column.

Edit the script by add download=1 after ?. 

Save and sync the device.

Credit to Abdul Munir for an idea and effort.