I understand you may think since it was on google you may freely use it but HowClever is right. You can get into BIG trouble for using that sort of thing without either paying for it or saying who is responsible for it, depending on what you allowed to do with picture,information etc.
That is why with assignments and such you have to have a bibliography and reference otherwise you are STEALING. I heard of a guy who did a huge speech in uni with a big media presentation. He ended up failing it, being removed from the course he was doing and having a huge lawsuit against him because he forgot to reference a short videoclip he used that wasn't his. Trust me there can be big concequences.