Windows 7: How to prevent Windows from caching my desktop wallpaper

Question

I have a service running that renders a changing wallpaper every 5 minutes or so, and replaces the current image file with the new one automatically (That is to say, new image but same filename). On Linux, the change is detected almost automatically, and so I have the most current wallpaper. However, on my Windows 7 machine (Which syncs the image with my Linux machine over Dropbox), it appears to cache the wallpaper from the last time I manually set the wallpaper. The image never changes, even if I restart.

Is there a way to make Windows detect the file change, or periodically refresh the wallpaper cache? I'd like to avoid third-party apps if at all possible.

Solution 1

Setting the wallpaper image copies it into the windows system folder in XP (and I assume Win 7). Try changing that copy to a shortcut to the file in your DropBox folder.

Solution 2

I'm interested in this subject and I've found the following:

• If you change the wallpaper from "Explorer" or the "Windows Gallery" then the image is copied to TrancodedWallpaper.jpg file in AppData\Roaming\Microsoft\Windows\Themes.

• If you change the wallpaper from "IE" then the image is copied to AppData\Roaming\Microsoft\Internet Explorer\Internet Explorer Wallpaper.bmp.

• If you change the wallpaper from "Firefox", the image is copied to AppData\Roaming\Mozilla\Firefox\Fondo de escritorio.bmp (in the Spanish version; I suppose Desktop Background.bmp in the English one).

The point is that, if you check HKCU\Control Panel\Desktop\Wallpaper you'll get the path to the current desktop, but only if Explorer/Gallery changed it. The IE/FF doesn't change this key but only the desktop.

The key HKCU\Software\Microsoft\Internet Explorer\Desktop\General\Wallpapersource is the source for your current desktop (for example, one desktop from the C:\windows\web\wallpaper folder).

So, it's not true that there is only one location for the wallpaper.

Comments

[Sasha Chedygov]

Did you write the service? If so, visit stackoverflow.com and ask there, because the service itself has to do this. If not, there probably isn't much you can do (although I won't give a definite answer).

[Chris Nava]

Then I would say you probably need a piece of software to update the cache. :-(