Is it religiously permissible for a maternal uncle living in the West to keep pictures of his nieces who do not wear the hijab, knowing that they asked him not to show them to anyone except women, and he is the only man in his household?

The ruling on photography and its types has been previously explained. The pictures given to the maternal uncle are permissible, and their purpose is to foster communication and acquaintance among relatives and mahrams. The maternal uncle was advised to keep them from strangers. There is no harm in this, provided the maternal uncle is trustworthy. There is no need to ask him to return them, to avoid suspicion and severing ties of kinship.