What commonality do buttons and images share in a user interface?

The correct answer highlights that both buttons and images can respond to a predefined set of events, such as clicks or hovers. This means that in a user interface, both elements are capable of reacting to user interactions, which enhances user experience and engagement.

For example, a button may trigger an action when clicked, while an image might have an associated event that occurs when a user hovers over it or clicks on it as well. This ability to respond to events is a crucial aspect of interactive design, allowing the application to react dynamically to user inputs.

Other options, while relevant, do not accurately represent a shared characteristic of both buttons and images. For instance, it's not true that both types of elements require event handlers at all times; an image can exist without needing to be interactive. Additionally, there are varied positioning rules depending on CSS styles, so they do not have identical rules. While being visibly distinct can enhance usability, it's not a requirement for both buttons and images in all contexts.