I don't know about the US, but here, once you purchase something it is yours to with as you wish. The only caveat is you can not make copies for distribution. The one you purchased you can burn, cut it up, sell it at 100 times what you paid for it or even make puzzles.
I use calendars for most of my picture puzzles as they are usually printed on good quality paper and if you get them after the year they are intended for they are almost given away. I have also used some plates from nursery rhyme books etc.