How to add alt text to images in a PDF

Alt text is the sentence a screen reader speaks in place of an image. Without it, a user hears "image" — or nothing — and misses the content.

Describe the meaning

Write what the image communicates, not what it literally is. "Sales up 20% year on year" beats "bar chart".

Mark decorative images

Purely decorative images should be marked as artifacts so screen readers skip them rather than announcing clutter.

Keep it concise

A sentence or two is usually enough. For complex figures, summarise and reference a fuller description nearby.