function GetFileSizeByName(FileName: String): Integer;
var
  FindData: TWin32FindData;
  hFind: THandle;
begin
  Result := -1;
  hFind := FindFirstFile(PChar(FileName), FindData);
  if hFind <> INVALID_HANDLE_VALUE then
  begin
    Windows.FindClose(hFind);
    if (FindData.dwFileAttributes and FILE_ATTRIBUTE_DIRECTORY) = 0 then
      Result := FindData.nFileSizeLow;
  end;
end;