Microsoft Personalization Gallery has released a theme called Bing Dynamic that automatically downloads and updates 2 Bing backgrounds to its wallpaper gallery every week through a RSS feed. It’s probably the first official theme published by Microsoft that uses the new theme feature that utilize the industry standard RSS feed as a wallpaper source. Not like a normal themepack file that opens Personalization and apply the them automatically, it pops up an Apply Theme window asking whether you want to download the attachments or not. After clicking on Download Attachments, it automatically subscribes the bundled feed in IE and downloads the Bing background pictures into the temp folder. The theme will be applied right after the attachments are downloaded. And since then, you will be able to get 2 more pictures every week without doing anything more. If you are wondering how to make a theme that is powered by a RSS feed, check out this post we revealed a while back. Or you can simply find out the secret by looking at the end of the themepack file in Notepad. That’s it, enjoy.