//Get an image from file    Image image = Image.FromFile("D://test.jpg");    Bitmap bitmap = new Bitmap("D://test.jpg");

using System;using System.Collections.Generic;using System.Drawing;using System.Drawing.Imaging;using System.IO;using System.Linq;using System.Text;namespace NetUtilityLib{  public static class ImageHelper  {    /// <summary>    /// Convert Image to Byte[]    /// </summary>    /// <param name="image"></param>    /// <returns></returns>    public static byte[] ImageToBytes(Image image)    {      ImageFormat format = image.RawFormat;      using (MemoryStream ms = new MemoryStream())      {        if (format.Equals(ImageFormat.Jpeg))        {          image.Save(ms, ImageFormat.Jpeg);        }        else if (format.Equals(ImageFormat.Png))        {          image.Save(ms, ImageFormat.Png);        }        else if (format.Equals(ImageFormat.Bmp))        {          image.Save(ms, ImageFormat.Bmp);        }        else if (format.Equals(ImageFormat.Gif))        {          image.Save(ms, ImageFormat.Gif);        }        else if (format.Equals(ImageFormat.Icon))        {          image.Save(ms, ImageFormat.Icon);        }        byte[] buffer = new byte[ms.Length];        //Image.Save()會改變MemoryStream的Position，需要重新Seek到Begin        ms.Seek(0, SeekOrigin.Begin);        ms.Read(buffer, 0, buffer.Length);        return buffer;      }    }    /// <summary>    /// Convert Byte[] to Image    /// </summary>    /// <param name="buffer"></param>    /// <returns></returns>    public static Image BytesToImage(byte[] buffer)    {      MemoryStream ms = new MemoryStream(buffer);      Image image = System.Drawing.Image.FromStream(ms);      return image;    }    /// <summary>    /// Convert Byte[] to a picture and Store it in file    /// </summary>    /// <param name="fileName"></param>    /// <param name="buffer"></param>    /// <returns></returns>    public static string CreateImageFromBytes(string fileName, byte[] buffer)    {      string file = fileName;      Image image = BytesToImage(buffer);      ImageFormat format = image.RawFormat;      if (format.Equals(ImageFormat.Jpeg))      {        file += ".jpeg";      }      else if (format.Equals(ImageFormat.Png))      {        file += ".png";      }      else if (format.Equals(ImageFormat.Bmp))      {        file += ".bmp";      }      else if (format.Equals(ImageFormat.Gif))      {        file += ".gif";      }      else if (format.Equals(ImageFormat.Icon))      {        file += ".icon";      }      System.IO.FileInfo info = new System.IO.FileInfo(file);      System.IO.Directory.CreateDirectory(info.Directory.FullName);      File.WriteAllBytes(file, buffer);      return file;    }  }}