It's invasive to take photos of someone without their knowledge.
James has a crush on Sarah and likes to look at pictures of her.
James wants to get new photos of Sarah.
James friends Sarah on Facebook and downloads every picture she uploads.
James follows Sarah around and takes candid photos of her when she's not looking.
James can tell his friends about this behavior because it's so common.
Sarah notices James and tells him she'll pepper spray him if he doesn't leave her alone.