I just hope the keys are not his home/office keys. Please do not secure the access to your digital life with an U2F token and break the security of your real life by putting a picture of your keys in the open...
https://www.youtube.com/watch?v=C5fLgxqWvJQ
Impressioning from a photo only poses a meaningful threat to genuinely high-security lock systems like the Abloy Protec or the ASSA Twin.
Upon saying that, I've added extra locks (bedroom locks) to the past 2 houses I've lived in, and the landlord had no issues, but that's student flats and cheap landlords.
That's not to mention that it's a lot easier to just break a window than pick a lock. I have never heard of a burglar breaking into a house by picking the lock. The sort of people that burgle residential houses tend not to be the sort of people with the skill, intelligence and finesse to pick locks.
Or in the case of residential interior doors, lean on the door kinda hard...