# What is alt text?

Source: https://epubcc.com/glossary/alt-text/ (updated 2026-11-04)

Alt text is a short text alternative for an image, written in the img element's alt attribute, that screen readers read aloud in place of the picture. Decorative images get an empty alt.

## Why it matters when you convert a PDF to EPUB

A PDF rarely carries usable alternative text for its images, and a converter cannot honestly write descriptions it does not know. The images in a converted EPUB keep whatever the PDF offers; good alt text still needs a person.

How EpubCC handles it: images extracted from the PDF are written with an empty alt attribute, because the engine has no reliable description to offer and does not invent one. A screen reader then skips them as decorative, so images that carry information, such as charts with data, need alt text added by a person after conversion.