What is the forbidden gaze? Is it permissible for a woman to scrutinize another woman? Is it permissible to scrutinize a girl's picture to imitate her hairstyle?

Looking with lust or fearing temptation is forbidden. Its rulings vary depending on what is being looked at:

A man looking at a woman: A young, non-mahram woman: It is absolutely forbidden to look at her 'awrah (private parts), and at her face and hands if temptation is feared. An elderly woman: The majority of jurists permit looking at her face and hands if she is not desired and not adorned, whereas the Shafi'is consider it absolutely forbidden. A young girl (pre-pubescent): Looking at her with lust is absolutely forbidden. Without lust, it is permissible to look at her entire body except for the private parts. Mahram women (close relatives whom one cannot marry): It is forbidden to look at them with lust, or at what is between the navel and the knee absolutely. Looking without lust at their places of adornment is permissible.

A man looking at another man: It is forbidden to look with lust, or at the 'awrah absolutely. Looking at anything else is permissible.

A man looking at the face of an attractive, beardless youth (Amrad): Looking at him with lust is forbidden. Some jurists consider it a greater sin than looking at a woman with lust.

A woman looking at a non-mahram man: It is forbidden to look at him with lust or if she fears temptation.

Looking by an intersex person (khuntha): They are treated according to the most cautious approach; they are considered a man when among women, and a woman when among men.

A woman looking at another woman: It is permissible to look at her entire body except for what is between the navel and the knee. It is forbidden if done with lust or fear of temptation. Imitating disbelieving or immoral women in hairstyles is prohibited.