(A) "You can see a bigger size if you click on the photo."
(B) "You can see the photo in a bigger size if you click on it."

Which do you prefer?
I do hear and see (A) a lot; but are the grammarians among you happy with it?
I prefer A. It's simple and direct. The grammar seems fine.

I have some reservations about B.

Ah, thanks! I was wondering if the noun "size" was used on its own outside context of clothes sizes etc., i.e. where each size is predetermined. ("This is size A, B, C...etc")