public class Thumbnail    {        private Image srcImage;        private string srcFileName;        /// <summary>        /// 创建        /// </summary>        /// <param name="FileName">原始图片路径</param>        public bool SetImage(string FileName)        {            srcFileName = FileName;            try            {                srcImage = Image.FromFile(srcFileName);            }            catch            {                return false;            }            return true;        }        /// <summary>        /// 回调        /// </summary>        /// <returns></returns>        public static bool ThumbnailCallback()        {            return false;        }        /// <summary>        /// 生成缩略图,返回缩略图的Image对象        /// </summary>        /// <param name="Width">缩略图宽度</param>        /// <param name="Height">缩略图高度</param>        /// <returns>缩略图的Image对象</returns>        public Image GetImage(int Width, int Height)        {            Image img;            Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);            img = srcImage.GetThumbnailImage(Width, Height, callb, IntPtr.Zero);            return img;        }        /// <summary>        /// 保存缩略图        /// </summary>        /// <param name="Width"></param>        /// <param name="Height"></param>        public void SaveThumbnailImage(int Width, int Height)        {            switch (Path.GetExtension(srcFileName).ToLower())            {                case ".png":                    SaveImage(Width, Height, ImageFormat.Png);                    break;                case ".gif":                    SaveImage(Width, Height, ImageFormat.Gif);                    break;                default:                    SaveImage(Width, Height, ImageFormat.Jpeg);                    break;            }        }        /// <summary>        /// 生成缩略图并保存        /// </summary>        /// <param name="Width">缩略图的宽度</param>        /// <param name="Height">缩略图的高度</param>        /// <param name="imgformat">保存的图像格式</param>        /// <returns>缩略图的Image对象</returns>        public void SaveImage(int Width, int Height, ImageFormat imgformat)        {            if (imgformat != ImageFormat.Gif && (srcImage.Width > Width) || (srcImage.Height > Height))            {                Image img;                Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);                img = srcImage.GetThumbnailImage(Width, Height, callb, IntPtr.Zero);                srcImage.Dispose();                img.Save(srcFileName, imgformat);                img.Dispose();            }        }        #region Helper        /// <summary>        /// 保存图片        /// </summary>        /// <param name="image">Image 对象</param>        /// <param name="savePath">保存路径</param>        /// <param name="ici">指定格式的编解码参数</param>        private static void SaveImage(Image image, string savePath, ImageCodecInfo ici)        {            //设置 原图片 对象的 EncoderParameters 对象            EncoderParameters parameters = new EncoderParameters(1);            parameters.Param[0] = new EncoderParameter(Encoder.Quality, ((long)100));            image.Save(savePath, ici, parameters);            parameters.Dispose();        }        /// <summary>        /// 获取图像编码解码器的所有相关信息        /// </summary>        /// <param name="mimeType">包含编码解码器的多用途网际邮件扩充协议 (MIME) 类型的字符串</param>        /// <returns>返回图像编码解码器的所有相关信息</returns>        private static ImageCodecInfo GetCodecInfo(string mimeType)        {            ImageCodecInfo[] CodecInfo = ImageCodecInfo.GetImageEncoders();            foreach (ImageCodecInfo ici in CodecInfo)            {                if (ici.MimeType == mimeType)                    return ici;            }            return null;        }        /// <summary>        /// 计算新尺寸        /// </summary>        /// <param name="width">原始宽度</param>        /// <param name="height">原始高度</param>        /// <param name="maxWidth">最大新宽度</param>        /// <param name="maxHeight">最大新高度</param>        /// <returns></returns>        private static Size ResizeImage(int width, int height, int maxWidth, int maxHeight)        {            decimal MAX_WIDTH = (decimal)maxWidth;            decimal MAX_HEIGHT = (decimal)maxHeight;            decimal ASPECT_RATIO = MAX_WIDTH / MAX_HEIGHT;            int newWidth, newHeight;            decimal originalWidth = (decimal)width;            decimal originalHeight = (decimal)height;            if (originalWidth > MAX_WIDTH || originalHeight > MAX_HEIGHT)            {                decimal factor;                // determine the largest factor                 if (originalWidth / originalHeight > ASPECT_RATIO)                {                    factor = originalWidth / MAX_WIDTH;                    newWidth = Convert.ToInt32(originalWidth / factor);                    newHeight = Convert.ToInt32(originalHeight / factor);                }                else                {                    factor = originalHeight / MAX_HEIGHT;                    newWidth = Convert.ToInt32(originalWidth / factor);                    newHeight = Convert.ToInt32(originalHeight / factor);                }            }            else            {                newWidth = width;                newHeight = height;            }            return new Size(newWidth, newHeight);        }        /// <summary>        /// 得到图片格式        /// </summary>        /// <param name="name">文件名称</param>        /// <returns></returns>        public static ImageFormat GetFormat(string name)        {            string ext = name.Substring(name.LastIndexOf(".") + 1);            switch (ext.ToLower())            {                case "jpg":                case "jpeg":                    return ImageFormat.Jpeg;                case "bmp":                    return ImageFormat.Bmp;                case "png":                    return ImageFormat.Png;                case "gif":                    return ImageFormat.Gif;                default:                    return ImageFormat.Jpeg;            }        }        #endregion        /// <summary>        /// 制作小正方形        /// </summary>        /// <param name="fileName">原图的文件路径</param>        /// <param name="newFileName">新地址</param>        /// <param name="newSize">长度或宽度</param>        public static void MakeSquareImage(string fileName, string newFileName, int newSize)        {            Image image = Image.FromFile(fileName);            int i = 0;            int width = image.Width;            int height = image.Height;            if (width > height)                i = height;            else                i = width;            Bitmap b = new Bitmap(newSize, newSize);            try            {                Graphics g = Graphics.FromImage(b);                g.InterpolationMode = InterpolationMode.High;                g.SmoothingMode = SmoothingMode.HighQuality;                //清除整个绘图面并以透明背景色填充                g.Clear(Color.Transparent);                if (width < height)                    g.DrawImage(image, new Rectangle(0, 0, newSize, newSize), new Rectangle(0, (height - width) / 2, width, width), GraphicsUnit.Pixel);                else                    g.DrawImage(image, new Rectangle(0, 0, newSize, newSize), new Rectangle((width - height) / 2, 0, height, height), GraphicsUnit.Pixel);                SaveImage(b, newFileName, GetCodecInfo("image/" + GetFormat(fileName).ToString().ToLower()));            }            finally            {                image.Dispose();                b.Dispose();            }        }        /// <summary>        /// 制作缩略图        /// </summary>        /// <param name="fileName">原图路径</param>        /// <param name="newFileName">新图路径</param>        /// <param name="maxWidth">最大宽度</param>        /// <param name="maxHeight">最大高度</param>        public static void MakeThumbnailImage(string fileName, string newFileName, int maxWidth, int maxHeight)        {            Image original = Image.FromFile(fileName);            Size _newSize = ResizeImage(original.Width, original.Height, maxWidth, maxHeight);            Image displayImage = new Bitmap(original, _newSize);            try            {                displayImage.Save(newFileName, GetFormat(fileName));            }            finally            {                original.Dispose();            }        }        /// <summary>        /// 生成缩略图,返回缩略图的Image对象        /// </summary>        /// <param name="rawImage">原始图片</param>        /// <param name="Width">缩略图宽度</param>        /// <param name="Height">缩略图高度</param>        /// <returns>缩略图的Image对象</returns>        public static Image MakeThumbnailImage(Image rawImage, int Width, int Height)        {            if (rawImage.Width == Width && rawImage.Height == Height)            {                return rawImage;            }            else            {                Size _newSize = new Size(Width, Height);                 return new Bitmap(rawImage, _newSize);            }        }        /// <summary>        /// 将字节数组转换为图片        /// </summary>        /// <returns></returns>        public static Image GetImageByBytes(byte[] bytes)        {            Image photo = null;            if (bytes != null && !bytes.Equals(null))            {                using (MemoryStream ms = new MemoryStream(bytes))                {                    try                    {                        photo = Image.FromStream(ms, true);                    }                    catch                    {                    }                }            }            return photo;        }        /// <summary>        /// 转化图片为Byte数组        /// </summary>        /// <param name="pb"></param>        /// <returns></returns>        public static byte[] GetBytesByImage(Image pb)        {            byte[] photo_byte = null;            if (pb != null)            {                using (MemoryStream ms = new MemoryStream())                {                    Bitmap bmp = new Bitmap(pb);                    bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Png);                    photo_byte = new byte[ms.Length];                    ms.Position = 0;                    ms.Read(photo_byte, 0, Convert.ToInt32(ms.Length));                    bmp.Dispose();                }            }            return photo_byte;        }    }