Hi,
I think it is not about how you get the images, it is about what you are going to do with them. If you want a huge storage of paper puzzles to solve yourself, of course it is ok to make printscreens and print them. But like Hagit said, you could just get in touch with her and ask for a higher limit. The puzzles you'll get will look much better, if only because of the resolution.
Also there is the possibility to buy books with puzzles from the
iGriddstore, have you considered that? That way you'll get mutiple small puzzles on one page, if that's the kind of puzzles you want and of course they'll all have a good layout and resolution.
Have fun solving!