Yeah, so, you shouldn't have sent the pics. That was really inconsiderate, she probably wants to eat that kind of thing too but she can't. I'd definitely be annoyed if it were me, but it'd be something that could be easily talked out. Like "hey, you gushing over that sandwich knowing it's something I can't eat (and probably really want to) was really inconsiderate, and while it's fine if you eat meat, please don't rub it in my face like that." Her reaction was definitely way over the top and unnecessary.

Try to talk it out, apologize, and see how she feels. I don't feel like it was about the sandwich itself, but rather about you bragging about something she can't have. But if she's really still saying you absolutely have to be vegan/eating meat is cheating/whatever nonsense, then that attitude is very immature and if she can't compromise with an issue as simple as this, I can't imagine how she'd react to more serious problems that will occur throughout a relationship/marriage.