asp.net webform 中怎样写二进制形式的<img src="" />形式

public void CheckCodes(string CheckCode)
{
Random rand = new Random();
int iwidth = (int)(CheckCode.Length * 15);
System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 22);
Graphics g = Graphics.FromImage(image);
g.Clear(Color.White);
//画图片的背景噪音线20条
for (int i = 0; i < 20; i++)
{
int x1 = rand.Next(image.Width);
int x2 = rand.Next(image.Width);
int y1 = rand.Next(image.Height);
int y2 = rand.Next(image.Height);
g.DrawLine(new Pen(Color.Silver), x1, x2, y1, y2);
}
//定义颜色
Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple, Color.YellowGreen };
//定义字体
string[] font = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体", "新宋体" };

//随机输出噪点
for (int i = 0; i < 50; i++)
{
int x = rand.Next(image.Width);
int y = rand.Next(image.Height);
g.DrawRectangle(new Pen(Color.LightGray, 0), x, y, 1, 1);
}

//输出不同字体和颜色的验证码字符
for (int i = 0; i < CheckCode.Length; i++)
{
int cindex = rand.Next(7);
int findex = rand.Next(6);

Font f = new System.Drawing.Font(font[findex], 12, System.Drawing.FontStyle.Bold);
Brush b = new System.Drawing.SolidBrush(c[cindex]);
int ii = 4;
if ((i + 1) % 2 == 0)
{
ii = 2;
}
g.DrawString(CheckCode.Substring(i, 1), f, b, 3 + (i * 12), ii);
}
//画一个边框

g.DrawRectangle(new Pen(Color.Black, 0), 0, 0, image.Width - 1, image.Height - 1);

//输出到浏览器
System.IO.MemoryStream ms = new System.IO.MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
HttpContext.Current.Response.ClearContent();
//Response.ClearContent();
HttpContext.Current.Response.ContentType = "image/Png";
HttpContext.Current.Response.BinaryWrite(ms.ToArray());
g.Dispose();
image.Dispose();
}