Is opening pornographic websites considered ʾzināʾ (fornication/adultery), and what is its ruling?

Opening pornographic websites and watching their content is a form of "fornication of the eyes," not the fornication that necessitates a prescribed punishment (hadd). This is based on the Prophet, peace and blessings be upon him, who said: "So the fornication of the eyes is gazing." Hearing and sight are blessings from Allah about which a servant will be questioned on the Day of Judgment. Whoever uses them in obedience to Allah will succeed, and whoever uses them in disobedience to Him will lose.