delphi 获取Webbrowser中的图片

procedure TfrmMain.DomImg2Image(wb:TWebBrowser);
var
  i:Integer;
  rang:IHTMLControlRange;
  s:string;
begin
  try
  s := (IHTMLDocument2(wb.Document).images.item('pic',EmptyParam) as IHTMLElement).getAttribute('src',0);
      rang:=((IHTMLDocument2(wb.Document).body as HTMLBody).createControlRange)as
        IHTMLControlRange;
      rang.add(IHTMLDocument2(wb.Document).images.item('pic',EmptyParam)as
        IHTMLControlElement);
      rang.execCommand('Copy',False,0);
      image1.Picture.Assign(ClipBoard);
  except
  end;
end;