How to set Win8 different versions of a background picture

In the WINDOWS8 developer Preview, the Metro menu background image is stored in the Shsxs.dll file in PNG format, and the official does not tell us how to customize the background. In Windows 8 Pre-Beta version Shsxs.dll This file no longer exists, the Metro menu background image is stored in the PNG format in the Imageres.dll file, we can change the background through the control Panel, but we can only use the official already built in the background.

Unlike the developer Preview version, in the Win8 pre-beta version, we no longer have the ability to customize an RGB three-color combination from the editor to the background, and we need a 8-bit indexed color picture. If we don't use this format, the new background will not be the original color of the picture.

As shown in the above picture is very ugly, if we want a good effect, we must use the original background palette through Photoshop and other tools to make a 8-bit indexed color picture.