Images on Flickr that are private or those for which the owner has opted-out of sharing will now deliver a pop-up that says \"this site doesn\'t allow pinning\" when a Pinterest user tries to save them. \"Only content that is ‘safe,’ ‘public’ and has the sharing button enabled can be pinned to Pinterest,” a spokesman for Flickr told the technology blog VentureBeat. Pinterest has seen a dramatic increase in users in recent weeks, as more and more people discover the joys of easily \'pinning\' a photo to the virtual pinboards that the company provides. However, the added attention that Pinterest has drawn has led to photographers expressing concern about the ease with which copyrighted images can be pinned and then re-pinned by other users. Last week Pinterest made code available so that website owners can prevent pinning. Copyright holders can also complain to Pinterest if an image appears on the site without their permission. Ben Silbermann, co-founder of Pinterest, said: \"We understand and respect that sometimes site owners do not want any of their material pinned.” Pinterest\'s terms and conditions say that it is the reponsibility of the user to ensure that they have permission to post an image. While many users see Pinterest as a good way to save pictures of clothes they would like to buy or possible paint colours for a new living room - images which are unlikely to draw copyright complaints - there are plenty of people who are sharing professional photographs, pictures of art or even quotations. In the long term, Pinterest could attempt to solve the problem by making deals with large rights-holding bodies, such as the major photo agencies, but for now site owners will have to take action themselves if they would prefer not to see their pictures on the website. From: Cnet