The goal here is to get the humans holding cellphones to take photos of you. In my experience the type of human didn't make a difference.
Go up to the target human and press
(Triangle on PS controller,
on Nintendo, F on keyboard) repeatedly to meow at them. Try not to get under their feet or else they will trip and storm off. They will not always take a photo! So if they ignore you, move on! Make sure if they start to take a photo of you, hold still till they walk away on their own!
Easiest way seems to be, stand in the park with the robot slide. Save, return to menu, load in. Spin your camera around and 2 or 3 people with cell phones should spawn in somewhat close. The humans in the park area walk to you in a nice triangle pattern making it easy to see everyone. Once you try 2 or 3 humans. Save, go to menu, load in and do it all again. I consistently got 2 out of 3 humans to take my photo doing this!
It also seems if they randomly sneeze while taking a photo it doesn't count. Sometimes they also chose to pet me instead of photograph me.