You have a valid problem. Possibly your family does not realize how they are inconveniencing you. Most likely your mother loves having you over so much that any excuse will suffice. At some point you will have to choose between being the ever-obliging child and taking a stand as an adult.
There is no disrespect in having a conversation with your mother along these lines:
You: Does the app I put on your camera not work?
Mother: What app?
You: Have you got your camera nearby? [Have her pick it up. Have her find the button. Walk her through unloading it baby-step by baby-step. Stay on the line with her and walk her through checking if the photos actually downloaded okay. When she assures you that they are fine, say something along the lines of:] Great! Now I'm going to let you get on with your evening. I'm kind of busy here myself.
Contact & Conditions
Her real fear might be losing contact with you. Plan to have Sunday dinner with her, or whatever works as quality time for both of you. Make it a regular habit to spend time with her so she knows she has not lost you. Let her know that the rest of your time is spoken for (even if for your own relaxation of for dating, etc.) but that she can count on these special times with you. Then make it happen.
If conditions need to be set for these times with your mother, weave them into the "contract" or agreement. You are an adult now and have adult responsibilities. If your mother is 45, you must be a fairly young adult whose responsibilities may increase in the coming decades. Take that into consideration.
Other Family Members
If other family members are also imposing on your time for your professional skills, use similar tactics. Some people prefer to make special allowances for parents, especially if siblings and cousins are working and able to pay their own tech support.
Here are some other lines you can use with family members:
I'm sorry you've got this problem but I've been working all day. I know this guy [name him; a name and face makes him seem more friendly] who has a business to help people with their home technology. He would be so happy to hear from you. Here's his number.
Sorry the solution we discussed last time isn't working. [That will inform them that they should be using the tips you gave them.] But call this guy [give number]. If I come over, I'll have to charge you because I do this for a living. [Obviously they will also have to pay this other guy but they never realized they had to pay YOU!]
Oh, I'm sorry that's still not working. I just got home and haven't had my supper yet. But if you can hold out till the weekend, I might be able to work you in. Just be warned that I do this for a living. Will you be paying by cash or credit card?
When your family realizes that you are not the free go-to person for all their tech problems, and that you will stay in contact socially, most likely things will balance up favourably for everyone. After all, they must feel somewhat guilty for taking advantage of you like this.