Jan, I went through something similar with my sister. When my grandmother died, I received a lot of her kitchen stuff, along with many photo albums. I was going to make copies for the rest of my siblings when I had the extra money.
My sister stayed with myself and my son for about 8 months. When she moved out, she had helped herself to several of those photo albums, along with some of my grandmother's kitchen stuff. I tried to forgive her for that. However, like you, I had a breaking point.
She moved back to Austin, Texas and eventually lost all of the contents in the storage locker she was renting which included all the items she took from my house. She didn't have the money for the storage locker so the contents were sold.
It is hard to forgive, especially when you sense no remorse for their actions. Does anyone in the family have copies of the photos that were lost?