Alt text: meaning, not description

Alt text is about communicating the purpose of an image, not just listing what it looks like. For example, a photo of a smiling team in a report about a successful project should say 'team celebrating project completion', not 'five people in suits standing around a table'. The key contrast: descriptive alt text tells you the pixels; meaningful alt text tells you the point. In an exam, you might be given an image of a bar chart showing sales growth — the alt text should state 'sales increased by 20% in Q3', not 'blue bars rising from left to right'.

A common trick to decide alt text is to ask: 'If I could not see this image, what one piece of information would I need to understand the page?' For decorative images — like a stock photo used purely as a visual break — the correct answer is empty alt text (alt=""), because describing it would waste a screen-reader user's time. Another hint: if the image has a caption that already explains it, the alt text can be brief or even empty. Watch out for exam questions that give you a chart and a caption; the alt text should not repeat the caption word-for-word but should add the key takeaway.

To test yourself, cover the image and read only the alt text — if you can grasp the image's role on the page, it is good. For a quick memory aid, think 'alt text = elevator pitch for the image'. If the image is purely decorative, your pitch is silence (empty alt). This rule saves you from over-describing and keeps your answer focused on accessibility, not aesthetics.