为什么这样压缩一下，图片文件大小变成0了？
procedure TForm1.Button1Click(Sender: TObject);

var jp:tjpegimage;

begin
jp:=tjpegimage.Create();
jp.LoadFromFile( 'e:\temp\1.jpg ');
jp.CompressionQuality:=50;
jp.Compress;

jp.SaveToFile( 'e:\temp\2.jpg ');
end;

end.

[解决办法]
Compress ： such as before streaming out when assigning a bitmap to a jpeg.