上传图片并生成缩略图

 protected static Image ThumailImage(string sourcePah, int thumbWidth, int thumbHeight)
        ...{
            int width = thumbWidth;
            int height = thumbHeight;
            FileStream source = new FileStream(file, FileMode.Open);
            System.Drawing.Image img = System.Drawing.Image.FromStream(source);
            if (img.Width / width > img.Height / height)
            ...{
                height = img.Width * height / img.Width;
            }
            else
            ...{
                width = img.Height * width / img.Height;
            }

            System.Drawing.Image thumbImage = System.Drawing.Image.FromHbitmap(new Bitmap(thumbWidth, thumbHeight, PixelFormat.Format32bppRgb).GetHbitmap());

            Graphics graphics = Graphics.FromImage(thumbImage);

            SolidBrush brush = new SolidBrush(Color.White);

            graphics.FillRectangle(brush, 0, 0, thumbWidth, thumbHeight);

            graphics.DrawImage(img, (thumbWidth - width) / 2, (thumbHeight - height) / 2, width, height);

            graphics.Dispose();
            source.Close();

            return thumbImage;
        }