Try this: Take a photo and upload it to Facebook, then after a day or so, note what the URL link to the picture is and then delete it.
出自-2010年12月聽力原文
In the case of Facebook, the company says data may hang around until the URL in question is reused, which is usually "after a short period of time", though obviously that time can vary considerably
出自-2010年12月聽力原文