Is the husband sinful for everyone seeing the naked picture he distributed? What is the ruling on the money earned from this act? And how does the husband seek forgiveness, knowing that he gives lessons at the mosque?

Distributing advertisements that promote vice and prohibited acts is not permissible in Islamic law, due to its nature of cooperating in sin and aggression, and guiding towards evil.

Ibn al-Qayyim said: "This sale involves assisting in sin and aggression."

It is stated in the Fiqh Encyclopedia: "Leasing for prohibited benefits, such as adultery, wailing, singing, and entertainment, is forbidden, and its contract is void, entitling no wage."

The remedy for this is sincere repentance, remorse, cessation, and a firm resolve not to return to it.

The earnings acquired from this are not lawful and must be disposed of by spending them on charitable and good causes for the poor and needy.