Answer:
At family gatherings, usually my cousins or I take photos of the event.
Explanation:
A verb is an action word that can only be properly used depending on the context of the sentence. In this case, you're talking about your cousins OR yourself. It makes a lot more sense when you use take instead of takes.
Proper use of "take": "She didn't take the envelope, as she knew it had a message she didn't want to hear."
Proper use of "takes": "He takes the coin and flips it.
