Is it obligatory to retrieve exchanged pictures between a young man and a young woman after repentance and ending the relationship, or is it permissible to remain silent to avoid communicating again?

It is impermissible for a woman to establish a relationship with a foreign man, due to the forbidden elements it entails. If you are quite certain that the man will return your photos without bargaining, then request them from him and return his photos to him. However, if you fear that he will exploit your request for blackmail or bargaining, then do not ask for them, and dispose of his photos that you have. Beware of the footsteps of Satan, and do not let thinking about the photos become a motivation to speak with him.