Change desktop wallpaper using code in .NET

Here's a class yanked from an app I wrote a year or two ago:

public sealed class Wallpaper
{
    Wallpaper() { }

    const int SPI_SETDESKWALLPAPER = 20;
    const int SPIF_UPDATEINIFILE = 0x01;
    const int SPIF_SENDWININICHANGE = 0x02;

    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    static extern int SystemParametersInfo(int uAction, int uParam, string lpvParam, int fuWinIni);

    public enum Style : int
    {
        Tiled,
        Centered,
        Stretched
    }

    public static void Set(Uri uri, Style style)
    {
        System.IO.Stream s = new System.Net.WebClient().OpenRead(uri.ToString());

        System.Drawing.Image img = System.Drawing.Image.FromStream(s);
        string tempPath = Path.Combine(Path.GetTempPath(), "wallpaper.bmp");
        img.Save(tempPath, System.Drawing.Imaging.ImageFormat.Bmp);

        RegistryKey key = Registry.CurrentUser.OpenSubKey(@"Control Panel\Desktop", true);
        if (style == Style.Stretched)
        {
            key.SetValue(@"WallpaperStyle", 2.ToString());
            key.SetValue(@"TileWallpaper", 0.ToString());
        }

        if (style == Style.Centered)
        {
            key.SetValue(@"WallpaperStyle", 1.ToString());
            key.SetValue(@"TileWallpaper", 0.ToString());
        }

        if (style == Style.Tiled)
        {
            key.SetValue(@"WallpaperStyle", 1.ToString());
            key.SetValue(@"TileWallpaper", 1.ToString());
        }

        SystemParametersInfo(SPI_SETDESKWALLPAPER,
            0,
            tempPath,
            SPIF_UPDATEINIFILE | SPIF_SENDWININICHANGE);
    }
}

I haven't tested it extensively, so use at your own risk.

If you want to temporarily set a desktop wallpaper without polluting the Windows settings history, here is a gist I made.

It backups the wallpaper history (stored in the registry) before setting the temporary wallpaper and you can restore it back afterwards.

https://gist.github.com/Drarig29/4aa001074826f7da69b5bb73a83ccd39

If you're using UWP in c# , here's the code I found here

using Windows.System.UserProfile; 

// Pass in a relative path to a file inside the local appdata folder 
async Task<bool> SetWallpaperAsync(string localAppDataFileName) 
{ 
   bool success = false; 
   if (UserProfilePersonalizationSettings.IsSupported())       
   {
       var uri = new Uri("ms-appx:///Local/" + localAppDataFileName);
       StorageFile file = await StorageFile.GetFileFromApplicationUriAsync(uri);
       UserProfilePersonalizationSettings profileSettings = UserProfilePersonalizationSettings.Current;
       success = await profileSettings.TrySetWallpaperImageAsync(file);
   }
}

Actually I think it can be more simple file.png is your photo ,it can be .jpg or something else

StorageFile file = await ApplicationData.Current.LocalFolder.CreateFileAsync("file.png", CreationCollisionOption.ReplaceExisting);
bool success = false;
UserProfilePersonalizationSettings profileSettings = UserProfilePersonalizationSettings.Current;
success = await profileSettings.TrySetWallpaperImageAsync(file);