So, when I go to system preferences then choose Desktop and Screen Saver there's the all the folders we all know, but when I select the + to add a new folder, I choose Desktop images and then there it appears a photo that was already deleted months ago! my desktop is totally clean but it still appears, I can still select it and ill have it as background.. How can I delete it from there? Because that picture its not very cool (NSFW). please help