The idea
Native elements supply established roles and keyboard behavior. Buttons perform actions; links navigate. Give controls accessible names that describe their purpose. Meaningful images need appropriate text alternatives, while purely decorative images can use empty alternative text. Extra ARIA should not contradict native semantics.
Worked example
A magnifying-glass submit button has the accessible name Search courses, not magnifying glass. A course-thumbnail image beside an already named link may be decorative depending on what it contributes. A meaningful diagram needs a useful description of its information.
Try it
List five controls on a fictional search page and assign native elements and names. Identify one decorative and one informative image. Write their alternative-text approach and explain why every image should not receive the same generic description.