private void GenereMiniature(Stream st, string directory, string filename, int Height)
{
     Bitmap thumbIndex = new Bitmap(st);
     int oldWidth = thumbIndex.Width;
     int oldHeight = thumbIndex.Height;

     double coeff = Convert.ToDouble(oldWidth) / Convert.ToDouble(oldHeight);

     int newHeight = Height;
     int newWidth = Convert.ToInt32(newHeight * coeff);

     Size ThumbnailsSize = new Size(newWidth, newHeight);
     Image oImg = Image.FromStream(st);
     Image oThumbNail = new Bitmap(ThumbnailsSize.Width, ThumbnailsSize.Height);
     Graphics oGraphic = Graphics.FromImage(oThumbNail);
     oGraphic.CompositingQuality = CompositingQuality.HighQuality;
     oGraphic.SmoothingMode = SmoothingMode.HighQuality;
     oGraphic.InterpolationMode = InterpolationMode.HighQualityBicubic;

     Rectangle oRectangle = new Rectangle(0, 0, newWidth, newHeight);
     oGraphic.DrawImage(oImg, oRectangle);
     oGraphic.Dispose();
     oImg.Dispose();

     oThumbNail.Save(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, directory + filename));
}