Images from CABook don't appear in encyclopedia window

[petermr]

This was solved but have now re-occurred. The images used to show, but are now blank. Tis may require guidelines to avoid it slipping in future

[aleenaharoldpeter]

The image rendering issue in the Climate Academy book viewer has been resolved in the aleena branch.

The problem occurred because the annotated book HTML referenced images located outside the encyclopedia/output directory, while the backend image inlining logic only permitted files within that folder. As a result, valid image paths under input/media were rejected during processing, causing the browser to receive unresolved relative paths that later resulted in 404 Not Found errors.

The validation logic was updated to correctly allow project-level media paths while still preserving the existing security checks and rendering pipeline behavior.

Most images now render correctly in the browser. However, a small number of images (approximately 6) still do not render because they use the .emf format, which is not properly supported in the current rendering pipeline/browser environment.