Bridesmaid showed my dress to people

I went wedding dress shopping with all of my bridesmaids and ended up finding my dress, and of course pictures were taken. We all parted ways after and I asked for the pictures not to be shown to anyone. Well my dad calls me later that evening and says that he saw one of my girls at an event and she asked him not once, but twice if he wanted to see pictures of it, he told her both times no I do not I want to wait until the wedding. He then told me she was showing the pictures to a few of her girlfriends, one of which is someone I’ve known my whole life and is also invited to the wedding. We all know this is a scared thing to not share the dress right!? How do I approach this with her? I honestly feel betrayed