After that is done, coonect your external hard drive to your PC.
Open Fie Explorer.
Left side (navigation pane ) open Onedrive.
Right side, all the folders in one drive will be listed there.
Right click at Pictures folder > click Move to > navigate to and click your external drive > click Move.
Pictures folder is now moved to the external hard drive. It no longer resides in Ondrive.
Go to Onedrive website > login > check to make sure Pictures folder no longer present.