My question is composed of two parts. First: What is the penalty for a Muslim man if he saw "very bad" pictures of girls either on TV or on the Internet? Second: How do you advise him to stop it?

All perfect praise be to Allaah, The Lord of the Worlds.  I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

My dear brother, seeing obscene pictures is prohibited regardless of whether it is real, in magazines or via the Internet. Allaah Says (what means): {Tell the believing men to lower their gaze, Allaah is Acquainted with what they do.}[Quran 24:30]

The Prophet, sallallaahu ‘alayhi wa sallam , was asked about the ‘surprise look’ and he said, “Avert your gaze.” Also, he, sallallaahu ‘alayhi wa sallam, informed us that such (unrestricted) gazing is the Zina (adultery and fornication) of the eyes.

May Allaah protect us all from the evil of such trials.

Allaah Knows best.