Big Youtuber used photograph without permission. Law related advice please?

My friend models for cosplay photography and 2 of her pictures were used in a Youtube video published by LifesBiggestQuestions, they have 577k subscribers and the video already has 200k+ views, pretty sure they've made some money out of that. My friend was not asked about permission to use those photographs,... show more My friend models for cosplay photography and 2 of her pictures were used in a Youtube video published by LifesBiggestQuestions, they have 577k subscribers and the video already has 200k+ views, pretty sure they've made some money out of that.
My friend was not asked about permission to use those photographs, she was no credited anywhere in the video or description and the watermarks that were on the photographs appear to have been removed in the video.
What kind of legal / illegal points can be brought up when messaging them about this? And what can be done if they don't amend this situation?
4 answers 4