How to save a WPF BitmapSource image to a file?

You need to use an encoder (subclass of BitmapEncoder). For instance, to save it to the PNG format, you do something like that :

public static void SaveClipboardImageToFile(string filePath)
{
    var image = Clipboard.GetImage();
    using (var fileStream = new FileStream(filePath, FileMode.Create))
    {
        BitmapEncoder encoder = new PngBitmapEncoder();
        encoder.Frames.Add(BitmapFrame.Create(image));
        encoder.Save(fileStream);
    }
}

By the way, note that there’s a bug in Clipboard.GetImage. It shouldn’t be a problem if you just save the image to a file, but it will be if you want to display it.

EDIT : the bug mentioned above seems to be fixed in 4.0