What should a husband do regarding his wife who appeared in photos with a strange man from her phone, despite her affirmation that the meeting was on a normal occasion and that she was photographed without her knowledge in an attempt by some of the attendees to cause harm to her husband and children?

What the wife did by mingling with a foreign man is a forbidden act and a wide door to fitna (temptation/strife). She must repent, seek forgiveness, and resolve not to return to it. As for the husband, we advise him to accept his wife's apology after she clarifies her mistake and promises to repent. He should also take good care of his wife and protect her, for men are qawwamun (maintainers and protectors) over women and are responsible for ensuring they fulfill Allah's rights and for restraining them from corruption. They must protect themselves and their families from the Fire, and every man is a shepherd and responsible for his flock.