Because it is an almost free service, (it runs off what turns up when Martin passes the cap round) it can't do certain things that cost too much money. Storing large numbers of great big files is one of them. Some folks, unable to figure out how to resize pictures to fit, used extrenal services like Photbucket to store them off site. When Photobucket decided to start charging for their service, these pictures, or the links to them, were lost, so the pictures were no longer available. The pictures, and the links to them, are the responsibility of the posters.
This is true of almost everything on the internet, when a site stops being around because nobody is paying to keep it there, it, and all of the information on it, vanishes.
Of course, some websites, having had the rent paid in advance, just keep displaying old, out of date information. A bit like an old motoring magazine in a doctors waiting room with adverts with prices in pre-decimal.