How to add more people in photo shuffle

Here is the problem as stated by another user: when I choose photo shuffle in the new customized Lock Screen, it gives me the option to choose people. My options are limited on the people and do not include ALL the people categorized in my Photos app. How can I add or removed people I want to see in the photo shuffle?

Here was a solution that worked for me: Go to Settings - to Photos - to Reset Memories and Reset People Suggestions - reset both - reboot the iPhone. More people showed up for my Shuffle Mix. Hope this helps someone.