Disregard the bad advise. People have the right to memories. If you are insecure then it is YOUR problem not his. If he is young you might brow beat him but you may make a wound that will never heal.
I did discuss to him how the pictures make me uncomfortable. I told him if he can get rid of them and he said that he would. I know that they are still there and he has not done anything with them. So I am not sure what to do but think "out of sight, out of mind".