In Jain dharma, the main bondage is caused by intention, attachment, and passions—especially kāma, rāga, and vikāra.

So:

• If you saw someone naked without lust, attraction, or attachment, the mental sin is much less than if desire arose.
• But deliberately looking at nudity is still not considered ideal in Jain conduct, because it can encourage carelessness, impurity of mind, and violation of modest restraint.
• For monks and nuns, this is a much stricter matter, as complete celibacy and vigilance are required.
• For lay followers, the best conduct is to avoid deliberate exposure and maintain shame, restraint, and purity of thought.

In short: without desire, the karmic fault is lighter; with deliberate intention, it is still not a wholesome act in Jain ethics.

If you want, I can also explain this according to Shwetambar and Digambar viewpoints.