Mobileread
Kindle book cover thumbnails disappearing
#1  pokeit 05-16-2020, 08:24 AM
Uploaded my kfx files (converted epubs) with Calibre send-to-device to my new Oasis (2019). The cover art thumbnails on the home screen briefly appeared correctly but almost instantly vanished and replaced by the default blank cover. The kfx files had previously been uploaded to my old Paperwhite (2018) with working cover art thumbnails; but I tested again today and it's now showing the same behaviour as the Oasis. The last time I successfully added a book to the Paperwhite must have been within the last two months, has there been a kindle software update since then?
Looking at the system/thumbnails directory, Calibre is creating a correct image, but after ejecting the kindle and re-plugging-in, the same thumbnail file has been replaced by the 'no image found' amazon thumbnail. If I understand correctly, normally the kindle asks amazon servers for artwork for a sideloaded book, so presumably it is now doing this regardless of the presence of art in the thumbnails folder?
[update] Just checked, when Airplane mode is on, the cover art remains; as soon as airplane mode is turned off, the cover art disappears.

I can work around by replacing the 'no image found' thumbnail with the cover art (using save cover to disk) on re-plugging-in, but I need to note which thumbnail goes with which book before I eject!
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#2  kovidgoyal 05-16-2020, 10:51 AM
I dont use KFX, so I dont know if this applies, but as long as you dont insert an ASIN into mobi/azw3, that is, as long as the book is recognized as a personal document the kindle wont try to download covers.
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#3  pokeit 05-16-2020, 01:31 PM
Thank you very much for the suggestion, but removing the Id tags from the metadata hasn't solved the issue. But given that the same kfx files have previously worked on my paperwhite I didn't really expect it to!
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#4  jhowell 05-16-2020, 02:08 PM
This does not only affect KFX format. The same thing is happening for AZW3 files. There is a thread on Reddit about it: All my book covers just disappeared?!

When a new book is found in storage that is marked as an Amazon-sourced book (EBOK) the Kindle software initiates the download of the cover thumbnail for that book based on its ASIN. It does this whether or not a thumbnail for that book is already present. In the past the request for the thumbnail image would fail because the ASIN is not a valid one at Amazon.

It appears that Amazon's servers have just been changed to return a 60x40 pixel image containing the text "No image available" instead of nothing. This overwrites whatever image thumbnail was set by calibre. And because it is smaller than the smallest allowed cover image size a generic cover thumbnail is instead shown for that book on the Kindle.

Marking the book as a personal document (PDOC) instead of an Amazon ebook (EBOK) won't work since Kindle firmware version 5.8.5 (Nov 2016) or later ignores thumbnail images for personal documents.

As far as I can tell the only fix would be to connect the Kindle again and resend the thumbnail after it has been overwritten by Amazon.
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#5  kovidgoyal 05-17-2020, 12:18 AM
Or keep your kindle in airplane mode. That should prevent amazons latest attempt to discourage you from side loading.
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#6  kovidgoyal 05-17-2020, 12:23 AM
Basically with your kindle in airplane mode, send the books to the kindle with calibre and the covers will remain. Alternately, if you want to keep wifi on, send the books once, disconnect kindle, wait for the covers to disappear, then reconnect and resend and the covers should stay in place.

And please do make some noise at amazons support forums about how this annoys you
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#7  pokeit 05-17-2020, 02:40 AM
Many thanks for the detailed replies.
Keeping my Kindle in airplane mode would work but is not feasible for me. Re-uploading also doesn't help, the book cover briefly reappears again but disappears when the kindle connects.
So it does look like my original workaround is the best route for now.

I will go and post on the amazon forums but I'm not hopeful...
Is there any possibility that Calibre could detect that a thumbnail it had written has been changed, and change it back?
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#8  kovidgoyal 05-17-2020, 03:16 AM
The kindle driver could probably be modified to keep two copies of each thumbnail on the device and simply refresh the copy amazon uses on every connect. It's kinda slow and expensive and stupid, but I guess that's the price one pays. But before doing this I want to be sure that amazon will actually refuse to change this broken ass behavior.
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#9  kovidgoyal 05-17-2020, 03:19 AM
Quote jhowell
Marking the book as a personal document (PDOC) instead of an Amazon ebook (EBOK) won't work since Kindle firmware version 5.8.5 (Nov 2016) or later ignores thumbnail images for personal documents.
But for PDOCs isnt the thumbnail read directly from the ebook file? In which case it should be effectively fine.
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#10  pokeit 05-17-2020, 07:34 AM
Quote kovidgoyal
The kindle driver could probably be modified to keep two copies of each thumbnail on the device and simply refresh the copy amazon uses on every connect.
It doesn't need to do it every time, only the first re-sync after initial upload, but I guess it would be simpler to just do it every time.
I've posted in the amazon forum and contacted amazon, we'll see what happens...

Quote kovidgoyal
But for PDOCs isnt the thumbnail read directly from the ebook file? In which case it should be effectively fine.
Just tested, no cover art when PDOC is selected for kfx conversion.
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