// Linux version is for Gnome only

static void wallpaper(S imageID) {

  wallpaper(loadImageAsFile(imageID), imageID);

}

// uses mode "fit to screen"

static void wallpaper(File img1, S description) {

  print("Setting wallpaper to: " + description + " (" + img1.getName() + ")");

  if (isLinux()) {

    print("Be sure to apt install pcmanfm!");

    S cmd = "pcmanfm " + bashQuote("--set-wallpaper=" + img1)

      + " --wallpaper-mode=fit";

    print(backtick(cmd));

  } else if (isWindows()) {

    File img = prepareProgramFile(#1004273, img1.getName() + ".bmp");

    saveBMP(loadImage2(img1), img);

    assertTrue(img.getAbsolutePath(), img.isFile());

    S cmd = "reg add \"HKEY_CURRENT_USER\\Control Panel\\Desktop\" /v Wallpaper /t REG_SZ /d " + bashQuote(img) + " /f";

    backtick(cmd);

    // Set to "fit" (WallpaperStyle=6, TileWallpaper=0) doesn't seem to work

    // So set to "center"

    cmd = "reg add \"HKEY_CURRENT_USER\\Control Panel\\Desktop\" /v WallpaperStyle /t REG_SZ /d " + 0 + " /f";

    backtick(cmd);

    cmd = "reg add \"HKEY_CURRENT_USER\\Control Panel\\Desktop\" /v TileWallpaper /t REG_SZ /d " + 0 + " /f";

    backtick(cmd);

    cmd = "RUNDLL32.EXE user32.dll, UpdatePerUserSystemParameters";

    backtick(cmd);

  } else

    fail("Don't know how to set wallpaper for your OS");

  print("Wallpaper set (hopefully)!");

}