Questioning boyfriend

I like taking pictures of my boyfriend and I every time we go on a date. It’s just something that not only important to me, but I feel like pictures hold sentimental value to it. Well today we went to the aquarium and I asked my boyfriend if we should take a picture. I only asked him to take a picture with his phone because mine ran out of batteries. He turned and told me he had no storage, but throughout the entire visit he was talking snaps and pictures of everything. This is the first time he’s been a little strange when I asked. I’m not sure what to think and two weeks ago he took the picture of our family(daughter, him, and i) off his phone and put in one of those default wallpapers. I’m not sure why, but I am starting to question him.