I dont know how/why the "Pictures" folder was added-how do I remove it?

[MacLuvin]

 

[DeltaMac]

The "Pictures" folder is one of the original folders in each user (home) folder. It is created at the time you set up a new user, along with others: Documents, Downloads, and Desktop (which is a special folder), Movies, Music, Public, and Sites. So, it is part of the original configuration of each user account.
And, I suspect that makes it one of the protected folder for your system.

 

[gilby101]

As @DeltaMac says. Also I believe you can't remove it from the Wallpaper settings. Just ignore it.