An oyster-reef cover model has one survey photo that already passed. Testers will change that source using a stated relation and check how the output must move. What technique is that?

One survey photo already passed. Testers change that source using a stated relation and check how the output must move. That is metamorphic testing: derive follow-up cases from a passed source via a metamorphic relation that ties the input change to the expected-result change. Adversarial testing, static drift testing, and A/B testing are different techniques.