I want to have a random wallpaper picture every time I log into my MacBook Pro with Retina Display laptop. Here is what I tried to do:

Settings > Desktop and Screensaver...

Clicked the + sign in the lower left hand corner to select my own unique pictures folder...

Clicked the "Change Picture When Logging In" button

Clicked the "Random Order Button"

After re-starting my laptop, I get the same wallpaper over and over no matter how many times I restart my Mac. There is no wallpaper randomness at all after log in.

I deleted the .plist file but that did not help.

I'm using Mountain Lion 10.8.2


- Ray