What is the ruling on imagining sin, and is it equivalent to committing it in terms of sinfulness? What is the ruling on watching regular and pornographic films? What are the ways to renew repentance and distance oneself from sins?

Intent and Niyyah have grades:

Passing thought, fleeting notion, and self-talk: A person is not held accountable for these. If they are good thoughts, one is not rewarded for them due to the absence of intent. Concern/Inclination (al-Hamm): If one inclines towards a bad deed but does not act upon it, no sin is recorded. If one acts upon it, one sin is recorded. As for inclining towards a good deed, one good deed is recorded. Determination (al-Azm): Verifiers (of religious rulings) hold one accountable for it, and its sin is less than that of the perpetrator, unless one is unable to act after forming the determination and doing what one can, in which case one is punished with the full punishment of the perpetrator.

A Muslim must ward off evil thoughts because they are the beginning of sin. Watching pornographic films is forbidden, and the sin of the perpetrator of indecency is greater. Watching films for entertainment is permissible if they are free from forbidden elements and do not prevent one from performing obligations.