uses Windows, ShlObj, ShellAPI;

function GetSpecialPath(CSIDL: word): string;

  var

  s: string;

begin

  SetLength(s, MAX_PATH);

  if not SHGetSpecialFolderPath(0, PChar(s), CSIDL, true) then s:='';

  Result:=PChar(s);

end;

begin

ShellExecute(0,'open','cmd.exe',Pchar('/c rundll32 "'+GetSpecialPath($26)+'\Windows Photo Viewer\PhotoViewer.dll",ImageView_Fullscreen G:\xxxx\ '+ParamStr(1)),nil,SW_HIDE);

//ShellExecute(0,'open','cmd.exe',Pchar('/c rundll32 "'+GetSpecialPath($26)+'\Windows Photo Viewer\PhotoViewer.dll",ImageView_Fullscreen '+ParamStr(1)),nil,SW_HIDE);

end.