Depends on the context. Some people can say it and it will sound like a compliment, others might say it as an insult and I'll take it as "Damn you are ugly in photos!"
In reality, I know I am not the most photogenic and I look better in person. A lot of people look better in person.
I'd rather look better in person than in pictures. One of my friends looks better in pictures..she is extremely photogenic but in person she is not that special and it's kind of disappointing.
I guess the best would be if a guy said "Your picture was pretty but it does nothing compared to how great you look in person". Basically reassure me that even though I look prettier in person my photo isn't butt ugly and you weren't expecting some ugly thing!
I think most people look better in real person than in pictures.
i'll take that as a compliment since society of today generally looks wayy better in pictures than in person (which is a bad thing). It would mean that I'm genuinely pretty and not just pretentiously pretty from pictures.