still has pics of his ex

so me and my bf were hanging out and he went thru his snap memories and i saw that he still has pictures of his ex’s in his memories. none of them are nudes or anything but just selfies from her on his snapchat. i didn’t say anything about it when i saw it but it’s been bothering me. like why do you still have pics of your ex when youre telling me that she was the worst and psycho and that he wants to be with me forever. i’m not gonna lie this relationship is very good and healthy but there’s things that keep bothering me such as this situation. i don’t know if i should say something about it or not or if i’m even allowed to be mad about it