[OPDS] Image link should return full-sized custom thumbnail if set

[awh-tokyo]

Steps to reproduce

1. Access the OPDS catalog and view an entry for any book without a custom poster set
2. Access the "image/thumbnail" link and note that it's a thumbnail of the first page
3. Access the "image" link and note that it's a the first page of the book
4. In the GUI, change that book's poster to a custom image
5. Access the OPDS catalog again

Expected behavior

The "image" link should be the original image uploaded as the custom poster, and the "image/thumbnail" link should be a thumbnail version of the same image.

Actual behavior

Although the "image/thumbnail" link contents have changed, it's a full-size image, not a thumbnail, and the "image" link is still the first page of the book.

Logs

No response

Komga version

0.163.0

Operating system

Linux, running the docker image

Other details

No response

Acknowledgements

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[gotson]

The links will not change, however the content returned by the image/thumbnail link changes. I just tried and it works as expected.

Are you testing via an OPDS client, or directly via the browser ?

[awh-tokyo]

I'm testing via a browser, but I tried clearing the cache and then using a different browser entirely so I don't think it's a caching issue.

The "image/thumbnail" contents do change when I upload a custom cover, though the returned image seems to be full-resolution for me, not a smaller version. That may be by design.

However, the "image" link remains a link to the first page of the book which still shows the original artwork:

<link type="image/jpeg" rel="http://opds-spec.org/image/thumbnail" href="/opds/v1.2/books/09ZF85SYB236B/thumbnail"/>
<link type="image/jpeg" rel="http://opds-spec.org/image" href="/opds/v1.2/books/09ZF85SYB236B/pages/1"/>

My expectation would have been that the "image" link would return the full-size poster image (either page 1 of the book, or whatever the user has uploaded through the edit book dialog), and the "image/thumbnail" would return a lower-resolution version of the same image.

[gotson]

I finally understood what you meant, sorry about that.

The spec says:

OPDS Catalog Entries may include atom:link elements to images that provide a visual representation of the Publication. For many Publications, these images will be the Publication’s artwork. This specification defines two Artwork Relations, which begin with http://opds-spec.org/image:

http://opds-spec.org/image: a graphical Resource associated to the OPDS Catalog Entry
http://opds-spec.org/image/thumbnail: a reduced-size version of a graphical Resource associated to the OPS Catalog Entry

The spec is vague enough so that whatever image could be used. However, the image/thumbnail should be the reduced-size version of the image link.

Which is not what is happening now.

So it could go one of 2 ways:

• either always display the first page, and forego custom thumbnails. It would be valid as per OPDS spec, but not in line with the rest of Komga.
• or have a way to provide the full size equivalent of the thumbnail.

Point 2 is what you suggest, however i can't remember whether Komga keeps the full size image in various cases.

In addition, the thumbnail endpoint for custom poster returns the full size of that image. It works for generated thumbnails because they have been resized already, but not for custom covers.

[github-actions]

🎉 This issue has been resolved in v1.0.0 (Release Notes)