[Alegun]

Средствами самого image

Код:

procedure TForm1.Button1Click(Sender: TObject);
var
 pol: array[0..2] of TPoint;
begin
 pol[0].x:= 10;
 pol[0].y:= 20;
 pol[1].x:= 70;
 pol[1].y:= 20;
 pol[2].x:= 70;
 pol[2].y:= 70;

 with Image1.Canvas do
  begin
   Brush.Style:= bsClear;
   Pen.Color:= clRed;
   Polygon(pol);
  end;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
 with Image1.Canvas do
  begin
   Brush.Style:= bsClear;
   Pen.Color:= clGreen;
   Rectangle(200, 200, 250, 250);
  end;
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
 with Image1.Canvas do
  begin
   Brush.Style:= bsClear;
   Pen.Color:= clBlue;
   Ellipse(170, 170, 100, 100);
  end;
end;

procedure TForm1.Button4Click(Sender: TObject);
var
 x,y,z: uint;
 cnv: TBitmap;
begin
 cnv:= TBitmap.Create;
 cnv.Assign(Image1.Picture.Bitmap);
 for X:=0 to image1.picture.width-1 do
  for Y:=0 to image1.picture.Height-1 do
   begin
    z:= image1.Canvas.Pixels[x,y];
    cnv.Canvas.Pixels[y,x]:= z;
   end;
 Image1.Picture.Bitmap.Assign(cnv);
 cnv.Free;
end;

Поворачивается лишь треугольник, ведь предупреждал