[angvelem]

Если не ошибся, примерно так:

Код:

var
  Buf : array[0..1023] of Byte;
  Stream : TMemoryStream;
begin
  Stream := TMemoryStream.Create;
  try
    Stream.LoadFromFile('MyBmp.bmp');
    Stream.Position := 54;
    Stream.Read(Buf, 1024);
  finally
    Stream.Free;
  end;
end;