procedure TFormMain.FlipBitmapRight(Sender: TObject);
var
  ClickedImage: TImage;
begin
  ClickedImage:=Sender as TImage;
  Edit1.text:=Files[((Sender as TImage).Tag)];
  RotateBitmap90(Clickedimage.Picture.Bitmap);
  (Sender as TImage).Picture.Bitmap:=ClickedImage.Picture.Bitmap;
end;

unit PhotoUses;

interface

uses Windows, Classes, Sysutils, Graphics;

function RotateBitmap90 (const bitmap : TBitmap) : TBitmap;

implementation

function BytesPerScanline(PixelsPerScanline, BitsPerPixel, Alignment: Longint): Longint;
begin
  Dec(Alignment);
  Result := ((PixelsPerScanline * BitsPerPixel) + Alignment) and not Alignment;
  Result := Result div 8;
end;


function RotateBitmap90 (const bitmap : TBitmap) : TBitmap;
var
  x, y : Integer;
  ps, ps1, pr, pr1 : PRGBTriple;
  bpss, bpsr : Integer;

begin
  if bitmap.PixelFormat <> pf24Bit then
    raise Exception.Create ('Invalid pixel format');
  result := TBitmap.Create;
  result.PixelFormat := bitmap.PixelFormat;
  result.Height := bitmap.Width;
  result.Width := bitmap.Height;

  ps1 := bitmap.ScanLine [bitmap.Height - 1];
  pr1 := result.ScanLine [0];

  bpss := BytesPerScanLine (bitmap.Width, 24, 32);
  bpsr := BytesPerScanLine (result.Width, 24, 32);

  for y := 0 to bitmap.Height - 1 do
  begin
    ps := PRGBTriple (PChar (ps1) + bpss * y);

    for x := 0 to Bitmap.Width - 1 do
    begin
      pr := PRGBTriple (PChar (pr1) - bpsr * x);
      Inc (pr, y);
      pr^ := ps^;
      Inc (ps)
    end
  end;
  GDIFlush
end;
end.