procedure TForm1.DMGraphicTarget1Drop(Sender: TObject; Acceptor: TWinControl;
  ThePicture: TPicture; X, Y: Integer);
var
  iString: string;
begin
  if Assigned(ThePicture) then
  begin
    { Assign ThePicture.bitmap to TImageEnView. }
    ImageEnView1.Bitmap.Assign(ThePicture.Bitmap);
    { Optionally stretch depending on checkbox state }
     if CheckBox1.Checked then
       ImageEnView1.Fit
     else
       ImageEnView1.Zoom := 100;
    { Show in the label what kind of object got dropped }
    case (Sender as TDMGraphicTarget).DroppedGraphicFormat of
      dgfBitmap: iString := 'Bitmap';
      dgfMetafile: iString := 'Metafile';
    else
      iString := '???'; { Should never happen! }
    end;
    Label1.caption := 'Dropped a '+ iString;
  end;
end;

procedure TForm1.ImageEnMView1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
var
  iBitmap: TBitmap;
begin
  { Detect a drag with any button }
  if DragDetectEx(ImageEnMView1.Handle, POINT(X,Y), Button) then
  begin
    { Tell the graphic source which button we got}
    DMGraphicSource1.MouseButton := Button;
    { Make a temporary bitmap }
    iBitmap := TBitmap.Create;
    try
      { Assign the ImageEnMView1.Bitmap to the temporary bitmap }
      iBitmap.Assign(ImageEnMView1.Bitmap);
      { Now, we have a bitmap, so assign it to the graphic source's picture }
      DMGraphicSource1.Picture.Graphic := iBitmap;
      { Now do the drag! }
      DMGraphicSource1.Execute;
      { In case we made a big bitmap, let it go.  Otherwise, it will live on unnecessarily in the Picture property of the TDMGraphicSource. }
      DMGraphicSource1.Picture := nil;
    finally
      { Clean up. }
      iBitmap.Free;
    end;
  end;
end;