The laws vary from country to country,but in the US,I'd say it depends more on the people that made the graphics than anything.If it's a big corporation,and they don't like the fact you used their logo than they can probably higher a good enough lawyer to get it ruled a violation of their copyright.If it was made by an individual I wouldn't worry about it.The best way to find out though would be to Email the people that made the logo and ask.