Heh, you payed for usage rights? That's awesome. I am glad to hear, truly!
Good luck on the project.
Well, even though I did, I didn't have to since the game is going to be free to download and free to play... Copyright laws here regarding creative content are fairly flexible in terms of reproduction as long as you change the content by at least 20% or (if unmodified) give it away for free as long as it is used in your own creative content. I think laws like this apply for a lot of things, including parodys of music and things like that... but yes I do have the right to use the pics even though I don't need it.
I payed for them because it was the only way I could get a hold of the exact kind of pictures I wanted.