Did you know that it is not legal to just pull pictures off web sites to use them for your own purposes? You can be sued for violating copyright protections on someone else’s work / intellectual property.
How do you avoid this dilemma? Make sure you are licensed to use the photos for your own purposes. There are free stock photo sites like Stock.xchng that allow you to use photos on your site for free, pending you agree to the photographer’s terms (for example, most photos on the Stock.xchng site restrict tasteless or pornographic sites from being allowed to use their images).