Paste images

main.cs

private void OnPaste(object sender, DataObjectPastingEventArgs e)
{
    HandleDataObject(e.DataObject);
    e.Handled = true;
}

private void HandleDataObject(IDataObject data)
{
    if (data == null) throw new ArgumentNullException(nameof(data));

    var formats = data.GetFormats();
    if (data.GetDataPresent(DataFormats.FileDrop))
    {
        string[] files = (string[])data.GetData(DataFormats.FileDrop, true);
        if (files != null)
        {
            foreach (var file in files)
            {

            }
        }
    }
    else if (data.GetDataPresent("PNG")) // Paint.NET
    {
        var pngData = data.GetData("PNG");
        var stream = pngData as Stream;
        if (stream == null)
            return;

        using (FileStream fs = File.Create("Img.png"))
        {
            stream.CopyTo(fs);
        }
    }
    else if (data.GetDataPresent(DataFormats.Bitmap))
    {
        BitmapSource bitmap = data.GetData(DataFormats.Bitmap) as InteropBitmap;
        if (bitmap == null)
            return;

        bitmap = new FormatConvertedBitmap(bitmap, PixelFormats.Bgr24, bitmap.Palette, 0);
        using (FileStream stream = File.Create("Img.png"))
        {
            var encoder = new PngBitmapEncoder();
            encoder.Interlace = PngInterlaceOption.On;

            var bitmapFrame = BitmapFrame.Create(bitmap);
            encoder.Frames.Add(bitmapFrame);
            encoder.Save(stream);
        }
    }
}