Image im1 = new Image();

                    BitmapImage bi = new BitmapImage(new Uri(Full_path));
                    im1.Source = bi;

                        if (this.Width > bi.PixelWidth) { grid1.Width = bi.PixelWidth + 4; this.Width = bi.PixelWidth + 4; }
                        if (this.Height > bi.PixelHeight) {grid1.Height = bi.PixelHeight + 24; this.Height = bi.PixelHeight + 24; }
                   
                    grid1.Children.Add(im1);
                    

 grid1.Width = double.NaN; this.Width = double.NaN;

grid1.Height = 200;
this.Height = 240;

 grid1.Margin = new Thickness(grid1.Margin.Left, grid1.Margin.Top + 40, grid1.Margin.Right, grid1.Margin.Bottom);