Cover metadata and cover pages differ
Readers may display the image marked as a cover in package metadata. A visible first-page cover can instead be an XHTML document that references an image. Updating metadata alone may leave that document pointing at an older resource.
Use two kinds of checking
The editor reopens its output and verifies basic package relationships. EPUBCheck covers many further rules involving semantics, links, accessibility and specification conformance. Neither replaces visually opening a book on your target device.
Inspect typography, chapter breaks, image dimensions and navigation after editing. Keep the original and edited copies separate until the new version behaves as intended.
Update both cover mechanisms when needed
Choose a PNG or JPEG cover and run the edit. The tool adds a kitforma-cover image resource beside the package document, marks the cover metadata and preserves other book resources. Look in the inventory to see the exact path. If the book’s first XHTML page still displays an older image, copy that chapter’s source and update its image reference relative to that chapter’s folder.
A package in EPUB/package.opf and a chapter in EPUB/text/cover.xhtml need different relative paths: the chapter might reference ../kitforma-cover.jpg. Do not copy a path mechanically without considering the chapter’s location. Existing CSS can also impose dimensions that crop or stretch a new image, which requires a visual check in the target reader.
Use a final acceptance checklist
Confirm the library thumbnail, visible cover page, title and author; open the table of contents; move sequentially through chapter boundaries; inspect a page with an image or special formatting. Then run EPUBCheck if the book will be distributed or submitted to a publishing platform. A successful local repackaging result is useful evidence that the archive structure survived, not a promise that every store, device or accessibility requirement is satisfied.