aspx.cs
using System;
using System.IO;
using System.Drawing;
using
System.Drawing.Imaging;
public partial class _2Stream :
System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs
e)
{}
protected void FileToStream(object sender, EventArgs
e)
{
//将JPG图片转化成字节数组
Image image =
Image.FromFile("E:/1.jpg");
//或者使用Server.MapPath
MemoryStream ms =
new MemoryStream();
image.Save(ms,
ImageFormat.Jpeg);
ms.Flush();
ms.Seek(0, SeekOrigin.Begin);
byte[]
buffer = new byte[ms.Length];
ms.Read(buffer, 0,
(int)ms.Length);
//遍历字节数组
for (int i = 0; i <
buffer.LongLength; i++)
{
message.Text +=
buffer[i].ToString();
}
//将字节数组转化成图像文件(自定义格式)并保存
MemoryStream
ms2 = new MemoryStream(buffer, 0, buffer.Length);
ms2.Seek(0,
SeekOrigin.Begin);
Image image2 =
Image.FromStream(ms2);
image2.Save("E:\\2.gif", ImageFormat.Gif);
}
}
aspx
<asp:Button runat="server" Text="转换" onclick="FileToStream"
/>
<asp:TextBox ID="message" runat="server" Width="100%" Height="600px"
TextMode="MultiLine" Wrap="true"></asp:TextBox>

参考资料
如何将jpg格式图像文件转化成一系列二进制数据,又如何将此二进制数据转化成jpg格式的文件?
http://www.cnblogs.com/begincsdn/archive/2005/07/12/191664.html
如何通过一个图片的URL得到该图片的尺寸大小?
http://www.cnblogs.com/begincsdn/archive/2005/07/12/191663.html