c# 图片转二进制/字符串 二进制/字符串反转成图片

    protected void Button1_Click(object sender, EventArgs e)
    {
        //图片转二进制
        byte[] imageByte = GetPictureData(Server.MapPath("./uploadfile/111.png"));
        //二进制转换成字符串
        string picStr = Convert.ToBase64String(imageByte);
        //输出字符串
        Response.Write(picStr);
        //字符串转二进制
        byte[] imageBytes = Convert.FromBase64String(picStr);
        //读入MemoryStream对象
        MemoryStream memoryStream = new MemoryStream(imageBytes, 0, imageBytes.Length);
        memoryStream.Write(imageBytes, 0, imageBytes.Length);
        //二进制转成图片保存
        System.Drawing.Image image = System.Drawing.Image.FromStream(memoryStream);
        image.Save(Server.MapPath("./uploadfile/222.png"));
    }

    /// <summary>
    /// 二进制流转图片
    /// </summary>
    /// <param name="streamByte">二进制流</param>
    /// <returns>图片</returns>
    public System.Drawing.Image ReturnPhoto(byte[] streamByte)
    {
        System.IO.MemoryStream ms = new System.IO.MemoryStream(streamByte);
        System.Drawing.Image img = System.Drawing.Image.FromStream(ms);
        return img;
    }

    /// <summary>
    /// 图片转二进制
    /// </summary>
    /// <param name="imagepath">图片地址</param>
    /// <returns>二进制</returns>
    public byte[] GetPictureData(string imagepath)
    {
        //根据图片文件的路径使用文件流打开，并保存为byte[]
        FileStream fs = new FileStream(imagepath, FileMode.Open);//可以是其他重载方法
        byte[] byData = new byte[fs.Length];
        fs.Read(byData, 0, byData.Length);
        fs.Close();
        return byData;
    }

    /// <summary>
    /// 图片转二进制
    /// </summary>
    /// <param name="imgPhoto">图片对象</param>
    /// <returns>二进制</returns>
    public byte[] PhotoImageInsert(System.Drawing.Image imgPhoto)
    {
        //将Image转换成流数据，并保存为byte[]
        MemoryStream mstream = new MemoryStream();
        imgPhoto.Save(mstream, System.Drawing.Imaging.ImageFormat.Bmp);
        byte[] byData = new Byte[mstream.Length];
        mstream.Position = 0;
        mstream.Read(byData, 0, byData.Length);
        mstream.Close();
        return byData;
    }