How Do Celebrity Fan Sites Obtain Photos of Celebrities?

[kashacin]

I hope this is not a taboo subject in this forum but I've always been curious about how some websites get celebrity photos. There are a lot of unofficial celebrity fan sites that publish pics of celebs the very same day the photo is taken! (or at least, the day after). Where do they get these photos? How does that work? What about the photographers who own the rights to these photos?