// declare a global TIEBitmap object that will be used in ImageEnMView1ImageIDRequestEx
var MyBitmap:TIEBitmap;

// subrectangles of "image.jpg" to show
const subrects:array [0..3] of TIERectangle = (
  (x:0;   y:0;   width:100; height:100),
  (x:120; y:200; width:80;  height:200),
  (x:0;   y:220; width:300; height:70),
  (x:0;   y:400; width:300; height:70)
);

// Load "image.jpg" and add rectangles defined in "subrects"
procedure TForm1.Button22Click(Sender: TObject);
var
  i:integer;
begin
  MyBitmap := TIEBitmap.Create(); // remember to Free!!
  imageenview1.io.loadfromfile('hongkong.jpg');
  for i:=0 to high(subrects) do
    ImageEnMView1.ImageID[ ImageEnMView1.AppendImage() ] := i;
end;

// copy the requested rectangle when necessary
procedure TForm1.ImageEnMView1ImageIDRequestEx(Sender: TObject; ID: Integer; var Bitmap: TIEBitmap);
begin
  Bitmap := MyBitmap;
  Bitmap.Allocate(subrects[ID].width, subrects[ID].height);
  ImageEnView1.IEBitmap.CopyRectTo(Bitmap, subrects[ID].x, subrects[ID].y, 0, 0, subrects[ID].width, subrects[ID].height);
end;