Błąd przy wgrywaniu zdjęcia Avatar do LongBlob w MySQL

MySql.Data.MySqlClient.MySqlException (0x80004005): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'avatar WHERE UserName = 'hesa656' Values(_binary '‰PNG

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   at MySql.Data.MySqlClient.MySqlStream.ReadPacket()
   at MySql.Data.MySqlClient.NativeDriver.GetResult(Int32& affectedRow, Int64& insertedId)
   at MySql.Data.MySqlClient.Driver.GetResult(Int32 statementId, Int32& affectedRows, Int64& insertedId)
   at MySql.Data.MySqlClient.Driver.NextResult(Int32 statementId, Boolean force)
   at MySql.Data.MySqlClient.MySqlDataReader.NextResult()
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()
   at SoundShadow.profile.pictureBox1_Click(Object sender, EventArgs e) in C:\Users\Robert\source\repos\SoundShadow\SoundShadow\profile.cs:line 97

            try
            {
                OpenFileDialog openFileDialog1 = new OpenFileDialog(); //wybierz avatar
                openFileDialog1.Filter = "Image Files(*.jpg; *.jpeg; *.gif; *.bmp; *.png)|*.jpg; *.jpeg; *.gif; *.bmp; *.png";
                if (openFileDialog1.ShowDialog() == DialogResult.OK)
                {
                    avatar.Image = Image.FromFile(openFileDialog1.FileName);
                    if (avatar.Image.Width == 800 && avatar.Image.Height == 800)
                    {
                        FileStream Stream = new FileStream(openFileDialog1.FileName, FileMode.Open, FileAccess.Read); //przekonwertuj na binary
                        BinaryReader brs = new BinaryReader(Stream);
                        images = brs.ReadBytes((int)Stream.Length);

                        try
                        {
                            String insertQuery = "INSERT INTO logindata avatar WHERE UserName = '" + logindata.userNick + "' Values(@img)"; //wgraj avatar
                            connectionstring.Open();
                            command = new MySqlCommand(insertQuery, connectionstring);
                            command.Parameters.Add("@img", MySqlDbType.LongBlob);
                            command.Parameters["@img"].Value = images;

                            avatar.Image = Image.FromFile(openFileDialog1.FileName);

                            if (command.ExecuteNonQuery() == 1)
                            {
                                MessageBox.Show("Pomyślnie wgrano avatar!");
                            }

                            connectionstring.Close();
                        }catch (Exception exe)
                        {
                            MessageBox.Show(exe.ToString());
                            Clipboard.SetText(exe.ToString());
                        }

                    }
                    else
                    {
                        MessageBox.Show("Obraz ma złe wymiary!");
                    }
                }
            } catch
            {

            }