如果Image1.Picture.graphic类型就是TJPEGImage的话，
那么可以直接使用Image1.Picture.SaveToFile保存为jepg文件
否则需要将其转换为TJPEGImage后再调用SaveToFile
(用image1.Picture.Graphic:=Tjpegimage(image1.Picture.Graphic);记得use jpeg)
其实说白了Image1.Picture是以其graphic的格式save
下面是delphi自带类型转换的例子，用它也可以！
procedure TForm1.Button1Click(Sender: TObject);
var
jp: TJPEGImage; //Requires the "jpeg" unit added to "uses" clause.
begin
jp := TJPEGImage.Create;
try
with jp do
begin
Assign(Image1.Picture.Bitmap);
SaveToFile('c:/oneeye.jpg')
end;
finally
jp.Free;
end;
end;
