function ExecAssociatedApp(const FileName: string): Boolean;
// Executes the application associated with the given file name. Returns true if
// application is started successfully and false if not
begin
  Result := ShellAPI.ShellExecute(0, nil, PChar(FileName), nil, nil, Windows.SW_SHOW) > 32;
end;

procedure TMainForm.Open1Click(Sender: TObject);
var
  iFilename: string;
begin
  iFilename := ImageEnMView1.MIO.ExecuteOpenDialog('','',false,0,'');
  if iFilename <> '' then
  begin
    Caption := iFilename;
    ImageEnMView1.MIO.LoadFromFile(Caption);
    ImageEnMView1.SelectedImage:=0;
    // Store the path to the associated document here
    ImageEnMView1.ImageTopText[ImageEnMView1.SelectedImage].Caption := 'C:\Users\Bill\Documents\Example.doc;
    ImageEnMView1ImageSelect(self, 0);
  end;
end;

procedure TMainForm.ImageEnMView1DblClick(Sender: TObject);
var
  iFilename: string;
begin
  // This will open the image in the associated application
  //iFilename := ImageEnMView1.MIO.Params[ImageEnMView1.SelectedImage].FileName;
  // This will open the associated document 
  iFilename := ImageEnMView1.ImageTopText[ImageEnMView1.SelectedImage].Caption;
  if not ExecAssociatedApp(iFilename) then
    ShowMessage('Unable to execute ' + iFilename);
end;