// Load input files
  IEBitmap1.Read('D:\MyPic1.png'); 
  IEBitmap2.Read('D:\MyPic2.jpg');
  
  // Get Left position for IEBitmap2
  iBitmap1Width := IEBitmap1.Width;

  // Resize IEBitmap1
  IEBitmap1.Resize(IEBitmap1.Width + IEBitmap2.Width, iMax(IEBitmap1.Height, IEBitmap2.Height), clWhite, 255, iehLeft, ievCenter);

  // Draw IEBitmap2
  IEBitmap2.RenderToTIEBitmapEx(IEBitmap1, iBitmap1Width, 0, IEBitmap2.Width, IEBitmap2.Height, 0, 0, IEBitmap2.Width, IEBitmap2.Height, 255, rfLanczos3, ielNormal, 1.0);

  // Save output file
  IEBitmap2.Write('D:\Output.png');

  // Load input files
  IEBitmap1.Read('D:\MyPic1.png'); 
  IEBitmap2.Read('D:\MyPic2.jpg');
  
  // Get Left position for IEBitmap2
  iBitmap1Width := IEBitmap1.Width;

  // Resize IEBitmap1
  IEBitmap1.Resize(IEBitmap1.Width + IEBitmap2.Width, iMax(IEBitmap1.Height, IEBitmap2.Height), clWhite, 255, iehLeft, ievCenter);

  // Draw IEBitmap2
  IEBitmap2.DrawToTIEBitmap(IEBitmap1, iBitmap1Width, 0);

  // Save output file
  IEBitmap2.Write('D:\Output.png');

unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants,
  System.Classes, Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs,
  Vcl.StdCtrls, Vcl.ComCtrls, Vcl.ExtCtrls, Vcl.ExtDlgs,
  imageenview, ieview, imageenio, imageenproc, hyieutils, hyiedefs,
  iexhelperfunctions;

type
  TForm1 = class(TForm)
    Panel1: TPanel;
    StatusBar1: TStatusBar;
    ImageEnView1: TImageEnView;
    Combine1: TButton;
    Open1: TButton;
    Open2: TButton;
    OpenPictureDialog1: TOpenPictureDialog;
    procedure Combine1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure Open1Click(Sender: TObject);
    procedure Open2Click(Sender: TObject);
  private
    { Private declarations }
    AIEImageList: TIEImageList;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Combine1Click(Sender: TObject);
{ Combine two pictures into 1 }
var
  iIEBitmap1: TIEBitmap;
  iIEBitmap2: TIEBitmap;
  iBitmap1Width: integer;
begin
  { Create a TIEBitmap to hold image 1 }
  iIEBitmap1 := TIEBitmap.Create;
  try
    { Create a TIEBitmap to hold image 2 }
    iIEBitmap2 := TIEBitmap.Create;
    try
      { Load input files }
      iIEBitmap1.Assign(AIEImageList.Image[0]);
      iIEBitmap2.Assign(AIEImageList.Image[1]);

      { Prevent getting a huge bitmap with large images by resampling both bitmaps }
      iIEBitmap1.Resample(1024, 768);
      iIEBitmap2.Resample(1024, 768);

      { Get Left position for IEBitmap2 }
      iBitmap1Width := iIEBitmap1.Width;

      { Resize IEBitmap1 }
      iIEBitmap1.Resize(iIEBitmap1.Width + iIEBitmap2.Width,
        iMax(iIEBitmap1.Height, iIEBitmap2.Height), clWhite, 255, iehLeft,
        ievCenter);

      { Draw IEBitmap2 }
      iIEBitmap2.RenderToTIEBitmapEx(iIEBitmap1, iBitmap1Width, 0,
        iIEBitmap2.Width, iIEBitmap2.Height, 0, 0, iIEBitmap2.Width,
        iIEBitmap2.Height, 255, rfLanczos3, ielNormal, 1.0);

      { Optional - Save output file }
      { iIEBitmap1.Write('D:\Output.png'); }

      ImageEnView1.IEBitmap.Assign(iIEBitmap1);
      ImageEnView1.Update;
      ImageEnView1.FitToHeight;

    finally
      { Free TIEBitmap1 }
      iIEBitmap1.Free;
    end;

  finally
    { Free TIEBitmap2 }
    iIEBitmap2.Free;
  end;
end;

procedure TForm1.FormCreate(Sender: TObject);
{ Form Create. }
begin
  { Enable gestures }
  ImageEnView1.Gestures.Pan.Enabled := True;
  ImageEnView1.Gestures.Zoom.Enabled := True;
  { Create a TIEImageList to hold the pictures }
  AIEImageList := TIEImageList.Create;
  { Register ImageEnIO file formats with TPicture }
  IERegisterFormats;
  { Set the OpenPictureDialog Filter }
  OpenPictureDialog1.Filter := GraphicFilter(TGraphic);
end;

procedure TForm1.FormDestroy(Sender: TObject);
{ Free the AIEImageList and UnRegister Formats }
begin
  AIEImageList.Free;
  IEUnRegisterFormats;
end;

procedure TForm1.Open1Click(Sender: TObject);
{ Open Picture 1 }
var
  iFileName: string;
  iIEBitmap: TIEBitmap;
begin
  AIEImageList.Clear;
  if OpenPictureDialog1.Execute then
  begin
    { Create a TIEBitmap to hold image 1 }
    iIEBitmap := TIEBitmap.Create;
    try
      iFileName := OpenPictureDialog1.Filename;
      { Open the file }
      iIEBitmap.IELoadFromFile(iFileName);
      { Save the image to the list }
      AIEImageList.AppendImageRef(TIEBitmap.Create(iIEBitmap), iFileName);
    finally
      { Free the IIEBitmap }
      iIEBitmap.Free;
    end;
  end;
end;

procedure TForm1.Open2Click(Sender: TObject);
{ Open Picture 2 }
var
  iFileName: string;
  iIEBitmap: TIEBitmap;
begin
  if OpenPictureDialog1.Execute then
  begin
    { Create a TIEBitmap to hold image 1 }
    iIEBitmap := TIEBitmap.Create;
    try
      iFileName := OpenPictureDialog1.Filename;
      // Open the file
      iIEBitmap.IELoadFromFile(iFileName);
      // Save the image to the list
      AIEImageList.AppendImageRef(TIEBitmap.Create(iIEBitmap), iFileName);
    finally
      { Free the IIEBitmap }
      iIEBitmap.Free;
    end;
  end;
end;

end.

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Combine Two Pictures Into One'
  ClientHeight = 299
  ClientWidth = 635
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  OnCreate = FormCreate
  OnDestroy = FormDestroy
  PixelsPerInch = 96
  TextHeight = 13
  object Panel1: TPanel
    Left = 0
    Top = 0
    Width = 635
    Height = 41
    Align = alTop
    BevelOuter = bvNone
    TabOrder = 0
    object Combine1: TButton
      Left = 171
      Top = 9
      Width = 75
      Height = 25
      Caption = 'Combine'
      TabOrder = 0
      OnClick = Combine1Click
    end
    object Open1: TButton
      Left = 9
      Top = 9
      Width = 75
      Height = 25
      Caption = 'Open 1'
      TabOrder = 1
      OnClick = Open1Click
    end
    object Open2: TButton
      Left = 90
      Top = 9
      Width = 75
      Height = 25
      Caption = 'Open 2'
      TabOrder = 2
      OnClick = Open2Click
    end
  end
  object StatusBar1: TStatusBar
    Left = 0
    Top = 280
    Width = 635
    Height = 19
    Panels = <>
  end
  object ImageEnView1: TImageEnView
    Left = 0
    Top = 41
    Width = 635
    Height = 239
    Background = clBtnFace
    ParentCtl3D = False
    EnableInteractionHints = True
    Align = alClient
    TabOrder = 2
  end
  object OpenPictureDialog1: TOpenPictureDialog
    Left = 35
    Top = 63
  end
end

...
{ Prevent getting a huge bitmap with large images by resampling both bitmaps }
      iIEBitmap1.Resample(-1, 768);
      iIEBitmap2.Resample(-1, 768);
...