原文网址：https://www.youyong.top/article/11593fcc4a3c5

图片转换成二进制互转

private void button1_Click(object sender, EventArgs e)
{
    string path = this.textBox1.Text;
    byte[] imgBytesIn = SaveImage(path);
    ShowImgByByte(imgBytesIn);
    //Parameters.Add("@Photo", SqlDbType.Binary).Value = imgBytesIn;
}
//将图片以二进制流
public byte[] SaveImage(String path)
{
    FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read); //将图片以文件流的形式进行保存
    BinaryReader br = new BinaryReader(fs);
    byte[] imgBytesIn = br.ReadBytes((int)fs.Length); //将流读入到字节数组中
    return imgBytesIn;
}
//现实二进制流代表的图片
public void ShowImgByByte(byte[] imgBytesIn)
{
    MemoryStream ms = new MemoryStream(imgBytesIn);
    pictureBox1.Image = Image.FromStream(ms);
}

将图片保存到数据库中，并从数据库中读取：

#region 将图片从数据库中读取
/// <summary>
/// 将图片从数据库中读取
/// </summary>
/// <param name="xs_ID">要读取图片的学号</param>
/// <param name="ph">pictureBox1控件名</param>
public void get_photo(string xs_ID, PictureBox ph)//将图片从数据库中读取
{
    byte[] imagebytes = null;
    getcon();
    SqlCommand con = new SqlCommand("select * from S_jiben where S_num='" + xs_ID + "'", link);
    SqlDataReader dr = con.ExecuteReader();
    while (dr.Read())
    {
        imagebytes =(byte[])dr.GetValue(18);
     }
    dr.Close();
    con_close();
    MemoryStream ms = new MemoryStream(imagebytes);
    Bitmap bmpt = new Bitmap(ms);
    ph.Image = bmpt;
}
#endregion
#region
public void SaveImage(string MID, OpenFileDialog openF)//将图片以二进制存入数据库中
{
    string strimg = openF.FileName.ToString(); //记录图片的所在路径
    FileStream fs = new FileStream(strimg, FileMode.Open, FileAccess.Read); //将图片以文件流的形式进行保存
    BinaryReader br = new BinaryReader(fs);
    byte[] imgBytesIn = br.ReadBytes((int)fs.Length); //将流读入到字节数组中
    getcon();
    StringBuilder strSql = new StringBuilder();
    strSql.Append("update S_jiben Set xs_photo=@Photo where S_num=" + MID);
    SqlCommand cmd = new SqlCommand(strSql.ToString(), link);
    cmd.Parameters.Add("@Photo", SqlDbType.Binary).Value = imgBytesIn;
    cmd.ExecuteNonQuery();
    con_close();
}
#endregion

原文网址：https://www.youyong.top/article/11593fcc4a3c5