Free one of the frozen big cats and click/tap on them when they appear, usually outside of your territory. It doesn't work with lucky. You have to buy the land that has a frozen animal starting with the red panda, free them by completing their tasks untill you get to the leopard (2nd) or panther (3rd). Free them them click/tap on them as much as needed.
I did it with the leopard because it's the first of the big cats that we can save, but I bet you can get the achievement by petting a panther too.

*continuation
I mean, the task with the icon of a camera vanished from the Mysterious Visitor mission's menu. The button with a camera that used to be on the top left was not present anymore since early november 2018 and I guess you could click/tap it to take a photo

PC - Take a screenshot. After I did it the button with the camera vanished from the menu the next time I entered the game