No you are not being a crazy person You are a normal women who feels that your boyfriend should be more concerned with you then her memories.
My question is why is he taking a chance on losing you simply to keep these things? The fact is some guys have a hard time with letting go.....which is fine when you are single and getting over the ex. With the amount of time you have been together this is a bit much. Since it is interfering with your relationship it is time to sit down and have a heart to heart talk with him.
You may want to offer a compromise.....let him know that while you understand his need to keep memories it is hurting your feelings and making you feel that he is placing the memories over you. Talk to him about renting a storage unit to store the things to not only keep them out of the relationship but to prevent them from being destroyed.
Ask him if you can set a time limit on either getting rid of the things or giving them back, such as a year. As far as the pictures, I would let him know how this makes you feel and ask that they be printed and stored with the other belongings as well. If he refuses then you have to do what is right for you......if you feel it is time to go then be honest with him. Let him know why you are leaving.....do not set it as a simple "Her things" issue....let him know the reason you are leaving is because him keeping her things while knowing how it upsets you makes you feel he is putting these memories over you.
Let him know that you still love and care about him, and if he is ready to get rid of the things or put them away some where then you will consider getting back together.
I wish you the best,