There may be some confusion here. It's legal for anyone to take a photo of anyone else in public, with few exceptions. TFA is not saying that ICE is forcing people to stand for a photo, it's saying that once ICE takes a photo, they can do stuff with it.
As an aside, it's my understanding that, unless someone is arrested, they're free to wear whatever clothing they like including something that covers their face. Probable cause is required for arrest, therefore ICE cannot force you to uncover your face. I'm not sure this has been tested much though, especially with folks temporarily detained.
Second aside, I anticipate a ton of lawsuits where folks give clear and convincing evidence of US citizenship and are unlawfully detained thereafter.