What is one's duty towards God, oneself, family, and husband regarding old photographs of a woman, and to resolve problems between the husband and his family, with the intention of traveling to them after a long absence?

The pictures showing a woman naked are dangerous and a source of temptation. You and your husband have done well by destroying your pictures. Continue to politely ask your family to destroy your pictures that they have, reminding them of Allah. If they refuse, then you have fulfilled your duty. Your general duties are to obey Allah and avoid disobeying Him, to obey and safeguard your husband, to maintain kinship ties, to honor your parents, and to train yourself in piety, in compliance with the words of Allah the Almighty: "O you who have believed, protect yourselves and your families from a Fire whose fuel is people and stones, over which are [appointed] angels, harsh and severe; they do not disobey Allah in what He commands them but do what they are commanded."