private void AddDrawingsFromXml()
 {
     var nodes = VmlDrawingXml.SelectNodes("//v:shape", NameSpaceManager);
     _images = new List<ExcelVmlDrawingPicture>();
     foreach (XmlNode node in nodes)
     {
         var img = new ExcelVmlDrawingPicture(node, NameSpaceManager, _ws);
         var rel = Part.GetRelationship(img.RelId);
         img.ImageUri = PackUriHelper.ResolvePartUri(rel.SourceUri, rel.TargetUri);
         _images.Add(img);
     }
 }
 internal ExcelVmlDrawingPicture Add(string id, Uri uri, string name, double width, double height)
 {
     XmlNode node = AddImage(id, uri, name, width, height);
     var draw = new ExcelVmlDrawingPicture(node, NameSpaceManager, _ws);
     draw.ImageUri = uri;
     _images.Add(draw);
     return draw;
 }