c# 把图片通过二进制读到postgresql数据库中

SQL_STR = "INSERT INTO /"D_AN/"( /"IMG1/",/"IMG2/",/"IMG3/",/"IMG4/") VALUES ((:p0),(:p1),(:p2),(:p3) )";
NpgsqlCommand command3 = new NpgsqlCommand(SQL_STR, _conn);
byte[] ib1 = new Byte[600000];
FileStream fs1 = new FileStream(aa1, FileMode.Open, FileAccess.Read); fs1.Read(ib1, 0, 600000);
byte[] ib2 = new Byte[600000];
FileStream fs2 = new FileStream(aa2,FileMode.Open,FileAccess.Read); fs2.Read(ib2, 0, 600000);
byte[] ib3 = new Byte[600000];
if (aa3 != "") { FileStream fs3 = new FileStream(aa3, FileMode.Open, FileAccess.Read); fs3.Read(ib3, 0, 600000); } byte[] ib4 = new Byte[600000];
if (aa4 != "") { FileStream fs4 = new FileStream(aa4, FileMode.Open, FileAccess.Read); fs4.Read(ib4, 0, 600000); }
command3.Parameters.Add(new NpgsqlParameter("p0", NpgsqlDbType.Bytea)); command3.Parameters.Add(new NpgsqlParameter("p1", NpgsqlDbType.Bytea)); command3.Parameters.Add(new NpgsqlParameter("p2", NpgsqlDbType.Bytea)); command3.Parameters.Add(new NpgsqlParameter("p3", NpgsqlDbType.Bytea));
command3.Transaction = _t;
Object result = command3.ExecuteScalar();
其中aa1....aa4是图片的路径