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
Researchers at Cambridge University have found that nearly half of the social networking sites don't immediately delete pictures when a user requests they be removed
出自-2010年12月聽力原文
Whether a deleted photo is immediately removed from the web.
出自-2010年12月聽力原文
In general, photo-centric websites like Flickr were found to be better at quickly removing deleted photos upon request