1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:

...
Img1: TImage32;
...

procedure TForm1.Button2Click(Sender: TObject);
begin

 Img1.Width := 800;
 Img1.Height := 800;

 Img1.Bitmap.LoadFromFile('c:\test.jpg');
 Img1.ScaleMode := smResize;
 Img1.Bitmap.StretchFilter := sfLinear;
 Img1.Bitmap.SaveToFile('c:\test2.jpg');

end;					

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:
30:
31:
32:
33:
34:
35:
36:
37:
38:
39:
40:
41:

procedure Tform1.transform(pic: String);
var tbmp: TBitmap32;
    bmp:  TBitmap;
    tjpg: TJPEGImage;
begin

      Img1.Bitmap.LoadFromFile(pic);

      tbmp := TBitmap32.Create;
      tjpg := TJPEGImage.Create;
      bmp := TBitmap.Create;

      tjpg.CompressionQuality := TrackBar1.Position * 5;

      tbmp.SetSize(StrToInt(Edit1.Text), StrToInt(Edit2.Text));

      Img1.Bitmap.StretchFilter := SF_CONSTS[Combobox1.ItemIndex];
      Img1.ScaleMode := smResize;
      tbmp.Draw(tbmp.BoundsRect, Img1.Bitmap.BoundsRect, Img1.Bitmap);

      try
        with bmp do
          begin
            Assign(tbmp);
          end;
      finally
       tbmp.Free;
      end;

      try
        with tjpg do
          begin
            Assign(bmp);
          end;
      finally
       bmp.Free;
      end;

      tjpg.SaveToFile('c:\test.jpg');
      tjpg.Free;    
end;