procedure TForm1.Button1Click(Sender: TObject);
var
  iInitialString: string;
  iCustomString: string;
begin
  if ImageEnMView1.SelectedImage <> -1 then
  begin
    iInitialString := 'This is a string assigned to ImageUserPointer';
    ImageEnMView1.ImageUserPointer[ImageEnMView1.SelectedImage] := @iInitialString;
    iCustomString := string(ImageEnMView1.ImageUserPointer[ImageEnMView1.SelectedImage]^);
    MessageBox(0, PWideChar(iCustomString), 'ImageEnMView ImageUserPointer To String',
      MB_ICONINFORMATION or MB_OK);
  end
  else
  begin
    MessageBox(0, 'Please select an image and try again.', 'No Selection', MB_ICONWARNING or
      MB_OK);
  end;
end;

type
  TFileDataRecord = Record
    Description : string[100];
    ID : Byte;
  end;


var
  POurRecord : ^TFileDataRecord;
begin
  // Allocate memory
  GetMem(POurRecord, SizeOf(TFileDataRecord));

  iNewIndex := ImageEnMView1.AppendImage('C:\SomeImage.jpg');
  POurRecord.Description := 'West Island';
  POurRecord.ID := 101;

  ImageEnMView1.ImageUserPointer[iNewIndex] := POurRecord;
end;



Later when removing this item from the ImageEnMView1 ensure you deallocate the memory...

for i := 0 to ImageEnMView1.ImageCount - 1 do
  Dispose(ImageEnMView1.ImageUserPointer[i]);

type
  TCacheRecord = Record
    ID: Integer;
    FileName: String[255];
    Checked, Failed: Boolean;
  end;

procedure FetchThumbNails;
var
  PCacheRecord: ^TCacheRecord;
begin
  // Allocate memory
  GetMem(PCacheRecord, SizeOf(TCacheRecord));
  ...
  // Fetch ThumbNails
  for i:= 0 to FileNames.Count-1 do begin
    ...
    j:= ImageEnMView0.AppendImage;
    ImageEnMView0.SetImageFromStream(j, ms);
    ...
    // Add Cache Record
    PCacheRecord^.FileName:= FillSpace(255); // ReSet
    PCacheRecord^.FileName:= FileNames[i];
    PCacheRecord^.ID:= j;
    ImageEnMView0.ImageUserPointer[j]:= @PCacheRecord;
    ...
  end;
  ...
  // TidyUp
  Dispose(PCacheRecord);
end;

procedure ReadCacheRecord(idx: Integer);
var
  FileName: String;
begin
  ...
  FileName:= TCacheRecord(ImageEnMView0.ImageUserPointer[idx]^).FileName;
  ...
end;

procedure ImageEnMView0DestroyImage(Sender: TObject; idx: Integer);
begin
  Dispose(ImageEnMView0.ImageUserPointer[idx]);
end;

procedure Move(idx: Integer);
var
  FileName: String;
begin
  ...
  FileName:= TCacheRecord(ImageEnMView0.ImageUserPointer[idx]^).FileName;
  ...
  if MoveFile(PWideChar(FileName), PWideChar(Path+FileName)) = True then begin
    Dec(TotalCount);
    TFileDataRecord(ImageEnMView0.ImageUserPointer[i]^).Failed:= False;
  end else begin
    ...
  end;
  ...
end;

type
  TFileDataRecord = Record
    Description : string[100];
    ID : Byte;
  end;


procedure TForm1.btnFillClick(Sender: TObject);
var
  POurRecord : ^TFileDataRecord;
  iNewIndex: Integer;
  i: Integer;
begin
  for i := 0 to ImageList.Count - 1 do
  begin
    // Allocate memory
    GetMem(POurRecord, SizeOf(TFileDataRecord));

    iNewIndex := ImageEnMView1.AppendImage(ImageList[i]);
    POurRecord.Description := 'West Island';
    POurRecord.ID := 101;

    ImageEnMView1.ImageUserPointer[iNewIndex] := POurRecord;
  end;
end;

procedure TForm1.btnShowInfoClick(Sender: TObject);
var
  POurRecord : ^TFileDataRecord;
begin
  if ImageEnMView1.SelectedImage < 0 then
    exit;

  POurRecord := ImageEnMView1.ImageUserPointer[ImageEnMView1.SelectedImage];
  ShowMessage(POurRecord.Description);
end;

procedure TForm1.ImageEnMView1DestroyImage(Sender: TObject; idx: Integer);
begin
  FreeMem(ImageEnMView1.ImageUserPointer[idx]);
end;