Op, your friend is categorically not a friend.
You need to think seriously about how you're going to distance yourself from her without drama or nastiness.
She sounds deeply unpleasant. A friend does not make negative comments about your weight etc. A bitch does though.
I can see why you're upset about not being invited to the evening wedding bash. It seems petty but I wonder if your 'friend' had a hand in it?
Her sending you photos etc seems a touch spiteful.
Personally I would message the bride and wish her a wonderful wedding day and a long, loving marriage.
And then, knowing you've done the right thing, enjoy yourself. Do something fun for you.
And avoid your 'friend' as much as you can.
Never bad mouth her or anyone in this wedding though because that will blow things up unnecessarily.
Just fade from their view and get on with having a good time with people who care and value you.
Be a bit more fussy and choosy about who you spend time with. If they make you feel shit about your weight or dress, then it's time to drop them!