Image not found
An image reference points at a file that isn't there. This isn't a Keystone check — Pandoc, the tool underneath, can't fetch the file and warns. The build continues, but the image is missing from your book.
What it looks like
With no assets/missing.png, the build prints:
WARN: Could not fetch resource assets/missing.png: replacing image with description
What it means
Pandoc resolves image paths as it builds. A path that doesn't resolve can't be fetched, so Pandoc puts the image's alt text in its place and carries on. Because it's a warning, a lenient build still succeeds with the image simply gone. Under strict mode it fails the build — which is how you catch a missing image before you publish.
Check the path, and build strict before you publish
Paths are relative to your project, so confirm the spelling and that the
file is under assets/ — see Figures & images.
Building strict stops the next one rather than
shipping the gap.
Related
- Undefined citation — the other common tool-origin warning that a lenient build lets through and strict mode catches.