[SOLVED] Header images royalty-free?

This might be a silly question, but I can't see a similar query in the forums.

I know the Atahualpa theme is released under the GPL 2 license, does that extend to the images for the header which are included?

I have a client who is really taken with them and wants to use them in his commercial site. Any copyright or royalty problems if he does? (I had a run-in with Getty Images a year or two ago, and do not want to repeat the experience!)

TIA
John