# What is an EPUB cover image?

Source: https://epubcc.com/glossary/cover-image/ (updated 2026-11-04)

The cover image of an EPUB 3 is the manifest item marked with the "cover-image" property; reading apps show it as the thumbnail in the library. It is usually a JPEG or PNG of the front cover.

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

A PDF has no notion of a cover: the first page may be a cover, a title page or a blank page. A converter can render the first page as the cover image, but it should not invent one, and a missing cover is not an error, just a plainer library thumbnail.

How EpubCC handles it: a full-page image on the first page of the PDF is kept at the start of the book as its cover page; full-page images on other pages are treated as scans and reported. The engine does not yet mark that image with the cover-image property, so some library views show a generic thumbnail instead of the cover.