ImageEnView2.Assign(ImageEnView1); // Copy content including Bitmap and IEBitmap from another TImageEnView, including layers and IO params
ImageEnView2.IEBitmap.Assign(ImageEnView1.IEBitmap);  // Copy only IEBitmap, does not copy layers and IO params
ImageEnView2.Assign(ImageEnView1.IEBitmap); // Copy only the ieBitmap of another TImageEnView does not copy layers and IO params

procedure TForm1.Button1Click(Sender: TObject);
var
  iIEBitmap: TIEBitmap;
begin
  try
    iIEBitmap := TIEBitmap.Create;
    iIEBitmap.Width := 640;
    iIEBitmap.Height := 480;
    iIEBitmap.PixelFormat := ie24RGB;
    iIEBitmap.Fill(clWhite);
    ImageEnView1.IEBitmap.Assign(iIEBitmap);
    ImageEnView1.IO.Params.Width := iIEBitmap.Width;
    ImageEnView1.IO.Params.Height := iIEBitmap.Height;
    ImageEnView1.IO.Params.BitsPerSample := 8;
    ImageEnView1.IO.Params.SamplesPerPixel := 3;
    ImageEnView1.Update;
  finally
    iIEBitmap.Free;
  end;
 end;