My fiancé has pic of ex wife in his wallet......

Is this something I need to be okay with. They share a daughter. So the ones with his ex, daughter and him I don't mind. But the ones of just him and her bothers me. She's mean to him and wishes he'd disappear from her life. She found a better man she's been with for over 4 years. We've been together over 2 years and I noticed it before, and hinted to him it was odd in the beginning. But now that we are engaged and together awhile. Shouldn't it be replaced with my picture or of us as a couple over the last couple years?