Hi there, your pictures are on, I can see them. That foot looks awfully sore, I'd say definitely an infection of some sort. I have no personal experience with frostbite, but many on here do and I'm sure you will hear from some of them soon. In the meantime, I just took part in a discussion about amputations in another thread, probably not something you want to think about, but it is worth reading and there are numerous happy outcomes. Good luck he's a handsome little guy.