Unlike in XP and Vista, in Windows 7, you can change the background without having to use any external software. For that, you must activate a function in the registry and then integrate a photo of a suitable size.
Activating a function: First,enter ‘regedit’ in the search field of the tart Menu and press Enter. Now confirm the question regarding the user account administration with ‘Yes’ and navigate to the key
On the right side in the window,search for the value ‘OEMBackground’. If that is not available, create it using ‘Edit| New | DWORD-value’. Double-click on the new entry to edit, change its ‘value’ to ‘1’ and confirm with ‘OK’. Then close the registry.
Preparing the Photo: Windows uses the file ‘backgroundDefault.jpg’ as the background picture and scales it to the current screen resolution, as long as no other file is available in the suitable pixel format. The files for special formats must be in the form ‘background 1024x768.jpg’. Here, the file names should include both values of the screen size. The best option is to edit the different image versions using a graphics program. While doing so, take care that the maximum file size does not exceed 256 Kb. If required, reduce the image quality of the JPG-file.
Copying in the System Folder :Now copy the edited JPG-files in the actual folder meant for OEM-providers ‘%windir% n\system32\oobe\info\backgrounds’. Since this is not available in most systems, you need to create it. For that, and to copy the files, you need writing rights. Therefore, open Windows Explorer with administrator rights by entering ‘explorer’ in the input field of the Start Menu, right-click on the program entry and then open ‘Run as administrator’ from the context menu. In Explorer,navigate to the folder ‘%windir%\system32\oobe\info’. Right-click on it, open ‘Properties’ and switch to the‘Security’ tab. There, click on ‘Edit’ and mark ‘Administrators’ as the group or user names. Activate the Option ‘Allow’ in the line ‘Complete access’ and confirm with ‘Accept’ and ‘OK’. After another click on ‘Yes’ you can create the sub-folder ‘\backgrounds’ and copy the JPG-pictures there.
From the next login, Windows 7 will greet you a background picture of your own choice.