This from cnet:
"Alida Saxon knew something was wrong last weekend when she saw that a thumbnail image on her blog that gets automatically fed from her Flickr page wasn't one of her own photos.Above photo via Flickr.
She clicked on the link for the image--a shot of a swimming pool--and was taken to her Flickr page, where she noticed that the pool image had mysteriously replaced one of her own shots.
"I thought my (Flickr) account had been hacked and some joker was swapping out images," the Springfield, Mass.-based artist wrote in an e-mail to CNET News.com. She went straight to the Flickr Help Forum and discovered that many other users were encountering the same problem of random photos replacing their photos on Flickr pages. Some of those new images, however, weren't as innocent as a swimming pool scene.