M.S.
A couple of things.
First of all, your mom is getting older. My experience of transitioning into my years as an elder ( I am 51 and menopausal )is that possessions that were vital a few years ago now look like 'just one more thing I have to deal with'--and I am ready to be done with them. It is almost like "do you want this?" is my mantra these days. It has nothing to do with loving or not loving the person who gave them to me. So, that's one thing. Another is that I can put my car keys down and not be able to find them 5 minutes later. If I am like that with my keys, which are merely inconvenient to lose, what am I going to be like with something valuable that I don't pay attention to on a daily basis? I gave my younger sister my great grandmother's ear rings for that reason.
The second thing I observe is that on some level you think your mom should keep everything because that is what you do:
I would never return my children's wedding pictures. I would change the frame or put them in an album but never return them unless I died. I'm wondering if that's because I am a huge scrapbooker/journaler and I almost live for pictures of my children.
It sounds like there is some sadness or resentment about the attention that your mother gives her clients that she did not and does not give to you. It sounds like you are using the return of the photos as one more way to prove that your mom doesn't love you. Can your forgive her for being who she is? Can you forgive her for doing what she does? What would you have to let go of to be able to simply love your mom exactly the way she is?
Ultimately, she is going to keep being who she is and doing what she does. You don't have the power to change any of that. You do have the power to change how these things impact YOU! AND there is power in having compassion for yourself and allowing yourself to feel what you feel, and share these feelings--BOT NOT IN A WAY THAT BLAMES THE OTHER PERSON OR MAKES THEM WRONG. i.e:
owning your feelings--
"I notice that I felt sad when you returned the pictures, I was hoping that you would want to keep them forever."
making your mom wrong for your feelings--
"How could you return the wedding pictures, you must not love me. You are so selfish."