public static void ResizeImage(string image, string Okey, string key, int width, int height, string newimagename)
    {
        System.Drawing.Image oImg = System.Drawing.Image.FromFile(HttpContext.Current.Server.MapPath("~/" + ConfigurationManager.AppSettings[Okey] + image));
 
        System.Drawing.Image oThumbNail = new System.Drawing.Bitmap(width, height);//, System.Drawing.Imaging.PixelFormat.Format24bppRgb

        System.Drawing.Graphics oGraphic = System.Drawing.Graphics.FromImage(oThumbNail);
 
        oGraphic.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
 
        //set smoothing mode to high quality
        oGraphic.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
        //set the interpolation mode
        oGraphic.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
        //set the offset mode
        oGraphic.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.HighQuality;
 
        System.Drawing.Rectangle oRectangle = new System.Drawing.Rectangle(0, 0, width, height);
 
        oGraphic.DrawImage(oImg, oRectangle);
 
        if (newimagename == "")
        {
            if (image.Substring(image.LastIndexOf(".")) != ".png")
                oThumbNail.Save(HttpContext.Current.Server.MapPath("~/" + ConfigurationManager.AppSettings[Okey] + image), System.Drawing.Imaging.ImageFormat.Jpeg);
            else
                oThumbNail.Save(HttpContext.Current.Server.MapPath("~/" + ConfigurationManager.AppSettings[Okey] + image), System.Drawing.Imaging.ImageFormat.Png);
        }
        else
        {
            if (newimagename.Substring(newimagename.LastIndexOf(".")) != ".png")
                oThumbNail.Save(HttpContext.Current.Server.MapPath("~/" + ConfigurationManager.AppSettings[Okey] + newimagename), System.Drawing.Imaging.ImageFormat.Jpeg);
            else
                oThumbNail.Save(HttpContext.Current.Server.MapPath("~/" + ConfigurationManager.AppSettings[Okey] + newimagename), System.Drawing.Imaging.ImageFormat.Png);
        }
        oImg.Dispose();
    }