This has happened before but not for a few months and I thought it was an isolated incident then.
SL 5.x x86 K fully update 2.6.38 kernel. Intel Core2 duo 2997, Nvidia GeForce 8500, Dell monitor 1920x1080.
After running the latest update to KDE 4.6.2 and rebooting I started Firefox (4) and a picture appeared in my Google home page. The picture is from a search I did a few weeks ago for pine shelving. Clearing the cache makes no difference, the picture cannot be captured by normal methods (I had to use a camera). It appears on top of most programmes that I start and will not react to any input. As far as the rest of the PC is concerned it doesn't exist. The only way I got rid of it was with a reboot.
I'm unable to post the images as "the board attachment quota has been reached". I will put them somewhere else and edit this post later.
Edit: Images here: http://www.sabayonspoiler.plus.com/file ... age.tar.gz