> I was speaking in general about the law, individual contracts nonwithstanding.
Then no. If your assistant snaps the photo and their contract doesn't try to address this, then they are the author (in US law) and could file for and fight you for, the copyright. You can credit each other as much as you want - US law doesn't care much about that. European law tends to care.
Then no. If your assistant snaps the photo and their contract doesn't try to address this, then they are the author (in US law) and could file for and fight you for, the copyright. You can credit each other as much as you want - US law doesn't care much about that. European law tends to care.