An EPUB cover needs more than an image file inside the package. For EPUB cover registration, verify the source path, the manifest inclusion, and the metadata role that identifies the asset as the cover. Placing a large picture at the start of chapter one is a different operation.
One cover and two inline images
The controlled three-chapter specimen used two inline PNGs and one separate cover PNG. Inspection returned three images, seven spine entries, three nav links, three NCX points, and valid=true. The observed asset total matched the inventory, and the generated EPUB and OPF were retained with hashes for reinspection.
A frequent failure is inserting the cover into body content without assigning the cover role, so the page appears in the book but not in a reader's library view. Repair that in the metadata path and re-export; do not rewrite chapter one. If the cover role is present but an inline figure is missing, return instead to the chapter-relative reference.
Accept the package when the source image exists, the file is included, and OPF identifies its cover purpose. Local validity does not promise retailer acceptance or identical bookshelf presentation across applications.
Separate three meanings of “the cover”
The source artwork is a file, the page-five selection is a book setting, and the packaged cover is a manifest role. They can disagree. Placing attractive art on the first content page does not automatically assign the package role that a library or storefront may use for a thumbnail. Troubleshooting begins by naming which of the three layers is missing.
Map the measured source paths
The two-chapter specimen uses one dedicated cover and two different inline images. Each inline image is referenced from manuscript markup; the cover is selected independently in book settings. Recording these routes before export makes the expected package inventory three rather than an unexplained folder total.
Revisit page five after moving artwork
When the original cover file moves, open the EPUB wizard's version/date/cover page and select the new path. Merely copying the artwork into the workspace does not update a saved reference. Reread the volume state or export plan and confirm that coverImagePath identifies the intended file before creating another package.
Compare plan and archive counts correctly
The measured export returned image count three, spine count seven, three nav links, three NCX points, and valid=true. The image count corresponds to one cover plus two content images. The spine count includes generated reading-order resources and should not equal the asset count. Treating every number as “pages” would manufacture a false failure.
Inspect the role inside OPF
Open the EPUB as a container and read content.opf. Confirm that the chosen resource is represented as cover material rather than merely present among generic images. Then inspect the chapter XHTML references for the two inline files. This package-level distinction is stronger than relying on a preview that happens to show the first illustration.
Reject the common false repair
If a reader displays no thumbnail, do not insert a second copy of the art at the beginning of chapter one. Return to the cover assignment, repair that route, export under a different filename, and compare the old and new OPF. Leave working inline references alone so the corrective change remains attributable.
Keep storefront behavior outside local proof
The archive is locally acceptable when all three images are included, no references are missing, the cover role is present, navigation files exist, and inspection returns valid. This does not guarantee retailer ingestion, identical cropping, or color appearance across devices. Those checks occur after structural acceptance.
An unrecognized EPUB cover is best diagnosed from source file to saved setting to OPF role. The three-image specimen supplies a small control: one cover route, two inline routes, and a reopened archive whose counts can be explained without guesswork.
The cover acceptance row should include the source digest, selected path, package identifier, cover relationship, and dimensions. A later replacement then changes one traceable row. It should not trigger unrelated rewrites of the two inline-image routes. If the new archive contains four images instead of three, inspect for an abandoned cover resource rather than declaring the extra item harmless.
Dimensions and appearance belong after role verification. A correctly identified cover may still have an unsuitable aspect ratio, tiny title lettering, or a color profile that renders poorly. Conversely, a beautiful first-page image can still be missing the package relationship. Structural and visual reviews answer different questions and should carry different evidence.
Storefronts may ingest, resize, or replace artwork. A changed download hash after distribution is therefore not automatically proof that local packaging failed. Repeat role, dimensions, and rendering checks in that environment. The local digest and counts identify the build that was uploaded, while the storefront preview identifies its transformed result.
This layered method narrows the phrase “not recognized.” If the file path is absent, repair source selection. If the file is packaged but lacks the cover role, repair metadata. If both are correct locally but the storefront remains blank, investigate ingestion rules. Each diagnosis begins at a different layer, which avoids repeatedly editing a working manuscript.
When several cover candidates exist, move rejected drafts away from the active selection path or name them unambiguously. Replacing bytes under the same filename can leave a preview or reviewer looking at cached artwork. A fresh filename and digest make the chosen revision explicit, and the reopened package can be checked for both the new resource and absence of the obsolete candidate.
After correcting the cover, rerun navigation and inline-reference checks as regression controls. The expected result remains three images with the two content routes intact. A narrowly scoped cover edit should not reorder chapters or break illustrations. Recording those unchanged values makes the recovery credible rather than treating a new thumbnail as proof that the whole book survived.