Well, it depends on how close you are with Tom.^^/
If you are quite close with him, you can comment on the picture in a casual way even though it is open to the public.
We have several speech levels in politeness and formality, and it wouldn't be easy for beginners to use them appropriately.
Unless the person you are talking to is a close friend, you'd better end with"-ㅂ니다" or "-요".
It would be the safest way.
The three speech styles below are commonly used in everyday Korean.
Tom is so perfect!
= 톰은 정말 완벽합니다! (formal)
= 톰은 정말 완벽해요! (informal)
= 넌 정말 완벽해! (without 요, among close friends, you don't need to mention his name^^)