Back to Error DirectoryW3C EPUBCheck Standard
OPF-051Critical Ingestion Error

Image dimensions exceed recommended size.

Image dimensions exceed recommended size.

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Fix all OPF-051 errors in your EPUB automatically

PreFlight checks for OPF-051 issues in memory and provides 1-click remediation during client-side packaging.

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What This Error Means in Plain English

EPUBCheck detected Image dimensions exceed recommended size.. Digital reading systems and bookstores require standard conformance to ensure compatibility across all reading apps.

Why Retailers & EAA Regulations Block This File

Automated book distributors (Apple Books, Amazon KDP, Kobo, and IngramSpark) run strict EPUBCheck validation on ingest and reject non-compliant files.

Technical Specification: W3C EPUBCheck rule OPF-051: Image dimensions exceed recommended size.

Manual Fix Instructions (for Sigil / Calibre)

  1. Locate the file and line flagged under rule OPF-051 in your EPUB editor (Sigil or Calibre).
  2. Apply the required syntax correction matching the OPF-051 specification.
  3. Re-pack and validate with PreFlight EPUB to confirm zero residual errors.