Очистить форму при перетаскивание цветных кусочков картинки на черно белое фото

var
 I, J : Integer;
  jpg : TJpegImage;
  buf : array[0..35] of TPoint;
begin
  Randomize;
  DoubleBuffered := True;
 
  jpg := TJpegImage.Create;
   if OpenPictureDialog1.Execute then
       jpg.LoadFromFile(OpenPictureDialog1.FileName);
  //jpg.LoadFromFile('2.jpg');
  bmp := TBitmap.Create;
  bmp.Assign(jpg);
 
  for I := 0 to 5 do
    for J := 0 to 5 do
    begin
      Buf[I * 6 + J].X := (J * 20) + I * 60 + 830;
      Buf[I * 6 + J].Y := (J * 80) + I * 10 + 10;
    end;
 
  for I := 0 to 5 do
    for J := 0 to 5 do
    begin
      Image[I * 6 + J] := TImage.Create(Self);
      with Image[I * 6 + J] do
      begin
        Parent      := Form9;
        Tag         := {35 -} (I * 6 + J);
        Width       := 133;
        Height      := 100;
        Left        := Buf[Random(36)].X;
        Top         := Buf[Random(36)].Y;
        OnMouseDown := ImageMouseDown;
        OnMouseMove := ImageMouseMove;
        OnMouseUp   := ImageMouseUp;
        Canvas.CopyRect(Image[I * 6 + J].Canvas.ClipRect, bmp.Canvas, Rect(J * 133, I * 100, J * 133 + 133, I * 100 + 100));
        Canvas.Brush.Style := bsClear;
        Canvas.Rectangle(Image[I * 6 + J].Canvas.ClipRect);
 
 
      end;
    end;
 
  jpg.Grayscale := True;
  bmp.Assign(jpg);
  bmp.PixelFormat := pf24bit;
  jpg.Free;
 
  Image1.Picture.Bitmap := bmp;
 
end;

PatBlt(Form9.Canvas.Handle, 0, 0,
Form9.ClientWidth, Form9.ClientHeight, WHITENESS);

for I := 0 to 5 do
    for J := 0 to 5 do
    begin
Image[I * 6 + J] := TImage.Create(Self);

for I := 0 to 35 
do Image[I].Free;