procedure TForm1.Button2Click(Sender: TObject);

 procedure EspejoVrt(BMPOrigen, BMPDestino:TBitmap);
 var
    f,c:integer;
    Ancho,Alto:integer;
    tmpBMP: TBitmap;
 begin
   {Bitmap temporal}
   tmpBMP:=TBitmap.create;
   with tmpBMP do
   begin
     Height:=BMPOrigen.height;
     Width :=BMPOrigen.width;
   end;

   {Inicializamos los límites de los bucles}
   {Initialize loop's limits}
   Ancho:=BMPOrigen.Width-1;
   Alto :=BMPOrigen.Height-1;

   {Copiamos los pixels}
   {Copy the pìxels}
   for f:=0 to Alto do
   begin
     for c:=0 to Ancho do
       tmpBMP.Canvas.Pixels[c,f]:=BMPOrigen.Canvas.Pixels[c,Alto-f];
   end;

   BMPDestino.Assign(tmpBMP);
   tmpBMP.Free;
 end;

 begin
   EspejoVrt(Image1.Picture.Bitmap,Image1.Picture.Bitmap);
 end;