When a gossip site posted a photo of a pregnant-looking Beyoncé, it probably didn’t anticipate the fallout: A major copyright decision that could imperil the site’s business model and undermine a legal defense used by other websites that depend on user content.

The decision, handed down Friday by a federal appeals court in California, came as a defeat for LiveJournal, which hosts the popular blog called “Oh No They Didn’t,” a forum for users to upload news about celebrities and chat about them.

The ruling came after a paparazzi operation called Mavrix, which the court describes as “specializing in candid photographs of celebrities in tropical locations,” sued Live Journal for copyright infringement over the Beyoncé photo and 19 other photos.