I've been in the niche for years, here's my advice from experience. If you use celebrity images, then make sure you throw up your disclaimer. Also, have a removal page so that photographers, celebrities, copyright holder can e-mail you to remove it. Stay away from Playboy, Hustler, Suz Randall, Perfect 10 (as shown in chilling effects link), and some other common companies who are very serious out enforcing copyright. If/when you are contacted, remove immediately. A normal C&D will give you 24-48 hours. Do not claim fair use. Do not back talk claiming whatever. Simply remove them, and e-mail them back verifying you've done so. In 10 years I've been contacted by 'maybe' 6 celebs/reps. I removed what they asked, end of issue. I have a friend in Oz who's been contacted by the companies mentioned. C&D, removed in 48 hours, end of issue. That said, the internet esquires will chime in that it's illegal, and that they can sue you, DMCA you out of google and the rest. Yes, they 'could', but as 10 years of experience will tell you, and common sense on the cost, most times you are asked to remove it and that's it. The people like Perez Hilton, and Pirate Bay who you read about are those who claim some kind of ownership, fair use. They are the one's who get sued because they are arrogant, and ignorant. If you should be contacted, remove immediately, do not repost. Normally that is the end of it.