We all know about Microsoft's latest Office suite "Office 2013" (codename Office 15) which is currently under development and a free Customer Preview version of Office 2013 can be downloaded using following link:
Microsoft has made many changes in this new version. The most noticeable change in Office 2013 is its UI. Microsoft has removed Aero glass from Office 2013 to match its interface with Windows 8. Microsoft has also removed colored themes from Office 2013 and has introduced new Metro style background images.
There are currently 6 background images available in Office 2013 as shown in following image:
By default no background image is set in Office 2013 programs but you can set a background image using Office Options. Open any Office program, click on File menu and then click on Options present in left sidebar.
Once you open Options window, you can change the background image using the drop-down box given in Office Background section as shown in following image:
Unfortunately, this method is not working for many people. Every time they try to change the background image and click on OK button, Office automatically resets the background image to None. There is no error message or instruction given to fix this issue.
In fact I also faced this problem in Office 2013 and after a little troubleshooting I found the solution.
The solution is sign in using a Windows Live ID and you'll be able to change or set background image in Office 2013 programs.
To sign in, click on "Sign in" link given below the titlebar buttons or click on File menu and then click on Account option present in left sidebar. Enter your Windows Live credentials and once you complete the sign in process, you'll be able to change background image.
Now you can change the background image using Options window or just click on your username or avatar given below titlebar buttons and select "Account settings" option. The same can also be accessed by clicking on File menu and then Account option in left sidebar.
As you can see in the above screenshot, you can quickly change the background image. It also shows live preview as soon as you hove mouse cursor over the given background images.
So the bottom line is that the background images can only be set or changed if and only if you are signed in using a Windows Live ID otherwise you'll not be able to use them.
In future if you want to sign out from Office 2013, open Account settings and click on "Remove" link given in user information section.
Keep in mind that signing out from Office 2013 will again reset background image to none. Its difficult to understand why a simple option to change background image is available to signed in users only? And if Microsoft really wants Office users to sign in to use this feature, they should put some kind of information or messages so that users can know how to use it. If a user is not signed in, the option to change background image should be greyed out.