Is watching pornographic and immoral films considered a major sin, along with the proof?

One should not ask whether a sin is minor or major in order to take it lightly, because going against Allah's command is disobedience, and the Prophet, peace and blessings be upon him, warned against belittling sins. The early Muslims believed that we should not look at the smallness of the sin, but rather at the greatness of the One who is disobeyed.

Scholars differ in counting and defining major sins, and a sinner may commit a sin they deem minor, yet it is major in the sight of Allah. A minor sin becomes major through persistence, for there is no minor sin with persistence, and no major sin with seeking forgiveness.

Scholars have counted looking at a non-mahram (definition) woman with lust, along with fear of temptation, as a major sin. Ibn Hajar al-Haytami said in Al-Zawajir: "The two hundred and forty-second, two hundred and forty-third, and two hundred and forty-fourth major sins are: looking at a non-mahram woman with lust along with fear of temptation, and likewise touching her, and likewise being alone with her." He also mentioned the hadith (definition) of Abu Hurayrah: "The adultery of the eyes is looking, the adultery of the ears is listening, and the adultery of the tongue is speaking..."