I wouldn’t say anything to them, its not your place. That’s like telling some one how ugly a dress is they just bought with out them asking for your opinion, its just rude. I do agree that those photos on that FB page are not that great, but there is nothing you can do about them. I would say to maybe message your family and say something like ” Hey I saw you got your photos done, you know I am always here for you if you want new photos in the future”. Keep it short and sweet and you don’t have to lie about not liking them, just don’t mention the quality at all. (Unless they ask, then its fair game lol )