Thanks a lot! Does that also count for general things that are more or less equal like lens flares or stuff like that? And what if I want things which I can't take Photos of? Does anyone knows good stock photo packs with many photos?
Derivative works (works made from other people's works) are owned by the original copyright owner(s). So... not you. If the photographer can recognize enough of their own work to say "HEY! You used my work!" they can theoretically take you to court.
The best way to get raw material is to shoot a fuckload of pictures. With today's digital cameras you can snap thousands of pictures and not pay for film development, so there's no reason not to take photos of everything you come across.