When should an image have null (empty) alt text?

An image should have null (empty) alt text when it is purely decorative. This means that the image does not convey meaningful information or content that is necessary for understanding the web page. By using empty alt text, developers signify to screen readers that the image can be ignored, allowing users who rely on assistive technologies to navigate the site without unnecessary distractions or redundant information. This practice enhances accessibility by ensuring that users focus on relevant content rather than being interrupted by images that add no functional value to the context.

In contrast, images that are descriptive in nature or provide essential information should always include meaningful alt text to convey their purpose and content. Complex images may also require detailed explanations to ensure understanding. Images that display descriptive text should include this information in the alt attribute, as it contributes to the overall message of the content. Therefore, only decorative images benefit from null alt text, streamlining the experience for users with disabilities.