you pick a picture then right click on it and choose set as desktop background.
Well, when I go into control panel -> change desktop background-> Internet explorer it says the directory "C:\Users\*username*\AppData\Roaming\Microsoft\Internet Explorer (1)". Not positive if its the same for everyone but is should at least tell you were its kept when selecting the background.
C:\Users\your - userID\Desktop
C:\users\jane\desktop
The desktop itself is a visual display of the desktop folders that reside in C:\Documents and Settings\(username/all users)\Desktop (unless an administrator has moved the folder to another location) When the computer loads, it looks to C:\Documents and Settings\All Users\Desktop for items to be displayed to all users and displays those in the main window. It will then look to ../*username*/desktop for personal desktop items to display if there are any.
In Windows, the default installation drive letter is C:, and the desktop folder will be in C:\Users\\Desktop\ (Windows Vista and newer) or C:\Documents and Settings\\Desktop\ (Windows XP), and for GNU/Linux distributions, /home//Desktop/(or simply ~/Desktop/ for any user that's logged in, will be directed to their own desktop folder)
Service
C:\users\jane\desktop
The desktop appears in the classic Windows format when you log on to the Windows XP computer as that user.
two users
messenger live
Remote Desktop Users
Parallels Desktop for Mac is a software package for Mac users to run Windows applications on their computers. This package is available from Amazon and many others