Use any public Picasa web album for your desktop wallpaper feed.

Use any public Picasa web album for your desktop wallpaper feed.

Windows 7 comes with some luscious eye candy for your desktop. The built-in themes feature striking photography. If you hanker for more wallpaper you can grab additional themes from Microsoft’s Personalisation Gallery. To change your theme, right-click an empty spot on the desktop, select Personalize from the context menu, click any of the displayed themes and close the Personalization explorer.

If you’re a wallpaper devotee, you’ve probably already scouted out many of the sites and services offering additional wallpaper, either free or for a price, such as Webshots and Windows7 Wallpapers. What you may not realise is that Windows 7 lets you download your wallpaper from an RSS feed. That means you can get a stream of wallpapers from any photo blog or website with a feed. The one restriction – apart from observing copyright permissions – is that the feed must wrap the photos in an enclosure. That restriction eliminates a fair number of sites, but there are plenty more to choose from. If your friends or family use Picasa Web Albums, for example, you can pull photos from any of their public web albums directly onto your desktop.

Not-so-free wallpaper

Be careful about downloading wallpaper from sites offering freebies. Some free wallpaper sites are safe, but others peddle spyware and other objectionable content. “Free” wallpapers and screensavers are a common source of computer virus infections.

Modifying a theme

A Windows .theme file

Windows 7 .theme files are simply text files containing a list of settings.

While it’s possible to create a theme from scratch, the simplest way to add a photo feed to your desktop is to grab one of the themes included with Windows 7 and modify it. Here’s how to do that using the Australia theme and a sample photo feed of scenery from New England set up on Picasa Web Albums.

  1. Click Start, type %localappdata% in the search box and press Enter.
  2. Open the Microsoft sub-folder, then the Windows sub-folder, then the Themes sub-folder and finally the Australia sub-folder. In that folder, you’ll find a sub-folder containing the wallpaper images used by the theme, plus the Australia.theme file.
  3. Click Australia.theme to select it, press Ctrl+C to copy the file to the clipboard, close the folder window and on the desktop press Ctrl+V to place a copy there.
  4. Rename this file New England.txt. Click Yes when you see the warning about changing the file extension – theme files are, infact, plain text files.
  5. Double-click New England.txt to open it in Notepad. Don’t be intimidated by the cryptic list of settings you see; you’re going to make a few simple edits and leave all the rest alone.
  6. In the [Theme] section change the DisplayName value to New England.
  7. Locate the [Control Panel\Desktop] section and set TileWallpaper=0 and Wallpaperstyle=0.
  8. Locate the [Slideshow] section and delete the entire ImagesRootPIDL setting including the long string of cryptic characters after it. You should be left with only two settings in the Slideshow section, Interval=1800000 and Shuffle=0 (the values for those settings may be different if you’ve changed the default theme settings at all).
  9. Add the following line to the [Slideshow] section:
    (Make sure there’s no space between the equals sign and the words.)
  10. Close New England.txt and save your changes, then rename the file to New England.theme.
  11. Double-click New England.theme. The Personalization explorer will open and you’ll be asked whether you want to subscribe to the rss feeds. Click Download Attachments then close the Personalization explorer.

Note: If you can’t see the ‘.theme’ extension on the filename in Step 3 above, you need to switch on file-extension display: Press Alt+T+O to open the Folder Options dialog box, click the View tab, remove the tick (checkmark) beside ‘Hide extensions for known file types’ and click OK.

That’s it. At first you’ll see one of the Australian wallpapers on your desktop. Windows needs to download the images from the RSS feed in the background, so wait a half a minute (longer if you have a slow Internet connection) and then right-click the desktop and select ‘Next desktop background’ from the context menu. You should see the first of the downloaded images centred on your desktop. You can check that the images are downloading properly by reopening the Personalization explorer and clicking Desktop Background. You should see the images, 17 in all, displayed.

Try this technique with other feeds, changing the name of the .theme file and the DisplayName and RssFeed values as needed. For instance, if you’re a fan of NASA’s image of the day, use either of these URLs in the RssFeed setting: (for large images) (for small images)

Because NASA publishes one image a day, you’ll start off with a single image in your NASA theme.

Accommodating large images

You may need to adjust some settings to display the feeds on your screen. The large NASA images, for example, may be too big to display at full resolution on your desktop. To accommodate these large images:

  1. Open the Personalization explorer and click Desktop Background.
  2. Select Fit from the Picture Position dropdown list.
  3. If you like, adjust the frequency with which the image changes, then click Save Changes and close the Personalization explorer.