private ExcelVmlDrawingPicture AddImage(Image Picture, string id, ExcelPackage.ImageInfo ii)
{
double width = Picture.Width * 72 / Picture.HorizontalResolution, //Pixel --> Points
height = Picture.Height * 72 / Picture.VerticalResolution; //Pixel --> Points
//Add VML-drawing
return _ws.HeaderFooter.Pictures.Add(id, ii.Uri, "", width, height);
}