思路:
存入到TMemoryStream
procedure TForm1.Button1Click(Sender: TObject);
var
MyJPEG : TJPEGImage;
MS: TMemoryStream;
begin
MyJPEG := TJPEGImage.Create;
try
with MyJPEG do
begin
Assign(Image.Picture.Graphic);
MS:=TMemoryStream.create;
SaveToStream(MS);
MS.Position:=0;