I imagine he just looked at the guys phone like:

blink blink

And was probably socially awkward about how to tell him thats not a train ticket.

While at the same time realizing that the cat looks socially awkward too. So this guy took a picture of his cat, while making some OTHER mistake that has the cat feeling unsure how to proceed.

Then he probably wondered all day what he said to that cat.

So, did the conductor accept it?

The cat tax value alone should cover the cost of a ticket.

valid ticket. good day sir

"Sir this ticket is for the wrong train. This is the A line. You're meant to be on the feline."

.. dad?

That's probably not the first time someone has showed him the wrong photo, and probably has seen worse photos

That could be taken as a threat.

Idk how it could be taken any other way. Those are murder eyes and bared claws. You might as well show a picture of a bloody chainsaw.

I would kneel, and tell him to board with an honorific.