To ensure that alternative text is displayed for an image if it fails to load, which attribute should be used?

The appropriate attribute to ensure that alternative text is displayed for an image if it fails to load is the "alt" attribute. This attribute is used within the <img> tag to provide a textual description of the image. If the image cannot be displayed for any reason, such as a broken link or slow internet connection, the alt text serves as a substitute to convey the purpose or content of the image to the user.

This practice not only improves accessibility for visually impaired users who rely on screen readers to interpret web content, but it also enhances the overall user experience by providing context in situations where images do not load correctly.

The src attribute specifies the URL of the image and is necessary for loading it, but it doesn't provide alternative information. The title attribute offers supplementary information when users hover over an image but is not displayed when the image fails to load. The href attribute is used in links to specify the destination of a link and is unrelated to images. Therefore, the alt attribute is the correct choice for presenting alternative text if an image does not load.