function Tform1.GetCodeImg;  

var url:string;  

response:TMemoryStream;  

jpg:TJPEGImage;  

begin  

   url:='https://kyfw.12306.cn/otn/passcodeNew/getPassCodeNew?module=login&rand=sjrand&0.3110086616057921';  

   idhtp1.Get(url,response);  

   jpg:=TJPEGImage.Create;  

   jpg.LoadFromStream(response);  

   img1.Picture.Assign(jpg);  

end;