{ 添加Timage并载入一幅24位或32位bitmap ;
添加TButton 并在OnClick 事件下加入下面代码}
procedure TForm1.Button1Click(Sender: TObject);
procedure FadeOut(const BMP:TImage; Pause:integer);
var
BytesPorScan: integer;
w,h: integer;
p: pByteArray;
counter: integer;
begin
{ 仅在24 位或32位色下有效}

If Not (BMP.Picture.Bitmap.PixelFormat in [pf24Bit, pf32Bit])
then raise exception.create(''''Error, bitmap format not supported.'''');

try
BytesPorScan := Abs ( Integer(BMP.Picture.Bitmap.ScanLine)-
Integer(BMP.Picture.Bitmap.ScanLine[0]));
except
raise exception.create(''''Error'''');
end;

{ 减小每个像素的RGB值}
for counter := 1 to 256 do
begin
for h := 0 to BMP.Picture.Bitmap.Height - 1 do
begin
P := BMP.Picture.Bitmap.ScanLine[h];
for w := 0 to BytesPorScan - 1 do
if P^[w] >0 then P^[w] := P^[w]-1;
end;
Sleep(Pause);
BMP.Refresh;
end;
end; {procedure FadeOut}

begin
FadeOut(Image1, 5);
end;