I viewed a topic on this site which hasn't really been answered for 4 years:
“How to go to the next/previous picture using the Windows 10 default photo viewer?”
On reading the responses, it gave me some clues and I was able to solve the problem.
When I tried to post the solution, I was unable as I must have 50 points or some such rubbish.
So the point is, how can you post an answer on SuperUser to let other people in on the answer, that has clearly been troubling people for years and (based on early comments) is actually now much worse than it was when the question was first raised. (ie buttons used to exist, but were greyed out. Now they don’t even exist)