Ok Mac, you win.. Now, can you let me now where you hid the white solid color.
As you can see, inside Macintosh HD→Library→Desktop Pictures, there is a Solid White.png background provided by Mac.
However, when you want to change your Desktop Background, inside the Desktop & Screen Saver Pane (can be accessed from Macintosh HD→Applications→System Preferences→Desktop & Screen Saver), the Solid White background image is nowhere to be seen.
Now, Mac, can you tell me where is it?
Oh.. I should have clicked there before. Mac completely disguises it.