.mobi-Books don't show Cover-Thumbnail when sent to personal documents service

[hyperchickens]

Hi!

Since a while now I've noticed that some of my books do not have a thumbnail preview in the cover view on my Kindle Paperwhite.

The thumbnails work with

• books that I've purchased on amazon
• books that I've converted from ePub to mobi, but only when they're transfered via usb, not if mailed to my kindle address

I tried converting a ePub to mobi, then putting it on the Kindle through Calibre (usb and no reconverting or anything), and then sending the same file to the personal documents service. The former results in correct display of cover thumbnails, the latter does not.

Is this known behaviour or am I doing something wrong??

Thanks!

[Kolenka]

Are you creating "both" style MOBI books (i.e. MOBI + KF8) when you convert them?

[tomsem]

I think the experiment that needs to be done is to compare the file which is downloaded from personal documents service with the one you sideload. PDS does muck with the metadata and it may be doing something with the cover image as well. Calibre (or KindleDump) might be able to show what is different.

Another idea: save off a copy of the downloaded file, remove the downloaded file, and then side load the copy. Does thumbnail show up? I

Kindle for Android shows cover thumbnails consistently for me, and even on my Paperwhite and Kindle Touch, a few items from PDS have thumbnails. Sideloaded content always has them (when there is a cover image in the file)

I believe thumbnails are generated on the device so it may be that PDS has done something that makes the thumbnail generation fail.

[hyperchickens]

Originally Posted by Kolenka

Are you creating "both" style MOBI books (i.e. MOBI + KF8) when you convert them?

That did it!! Thanks so much, this had been bugging me for a week now..

[hyperchickens]

Hi!

So apparently that worked fine for some weeks, but now the Personal Documents service constantly sends me books that don't show the cover in the Paperwhite.

Even the very same books that I tried out before, and that did show covers when using the PDS, and that still are on my device - when I re-download them, I get a file that doesn't show its cover.

So that is either a really strange problem with the PDS or, somehow my Paperwhite does something when downloading the book or is not downloading the *right* version (I did select both KF8 and old format in Calibre)

I'll try to see if there's any difference in the files as proposed by tomsem..

[hyperchickens]

So, for anyone interested..

It appears that when downloading your personal document, either on the side of Amazon or locally on the Kindle, sometimes the covers get downloaded and correctly extracted, and sometimes they don't (this is for the very same file, so the file is correctly formatted)

Maybe it has something to do with the firmware of the kindle, or it's just magic. Who knows.

[Notjohn]

Perhaps "personal document service" is a different route, but the mail-to conversion once popular with Kindle publishers is no longer much used because it builds only a Mobi 7 book and ignores the newer KF8 format.

(One usually emailed a *.doc file or a double-zipped html-plus-images archive. I have no idea what would happen with a *.mobi file downloaded from the KDP.... But in that case, what would be the point in emailing it, since it is already Kindle-ready?)

[hyperchickens]

Originally Posted by Notjohn

.... But in that case, what would be the point in emailing it, since it is already Kindle-ready?)

Synchronized reading progress among all your devices plus annotations backup

[Notjohn]

So you're uploading a document to the KDP, letting it convert, downloading the converted book file, and emailing it to your Kindle so that you can use it like a published book without having published it?

Wouldn't it be quicker and easier to publish the book, then to buy a copy?

(Just trying to understand the logic of it!)

[hyperchickens]

No wait, you just email it to Amazon and it gets forwarded to your Kindle and archived. Why would I want to publish a third party .mobi book???

[quiris]

Message From Amazon Customer Service:

Hello,

I'm sorry for all the inconvenience this might have caused.

I understand you'd like to access the feature of Cover-Thumbnail in Cover View for KF8 format books and personal documents.

As this feature is currently not available, I’ve forwarded your concern to our development team and we'll consider your feedback as we plan further improvements. We're regularly working on improvements to your Kindle experience. I've let the Kindle team know you're interested in this feature.

We are trying very hard to establish ourselves as a successful online digital store and can assure you of numerous changes in very near future which will enable us to achieve our goal and Customer feedback like yours is very important in helping us continue to improve our website and services.

[tomsem]

Out of 50 or so of the personal documents that should have thumbnails, a couple of mine actually do. Curiously, I'm unable to remove these two items via the UI (it offers to Remove but does not do so when asked). I think I initially had sideloaded them and later put them in the cloud.

Thumbnail images are stored in /system/thumbnails. It seems they stick around even after a book is removed from the device (so many Cloud items have cover images). Most of the filenames seem to include ASIN as part of the name and can be matched up to the corresponding document (if it is on the device). But in the case of the two personal documents, the name is 'generic', e.g. "thumbnail_5598.jpg". So the mapping from one to the other must be something stored in a database somewhere.

[Josieb1]

All my personal documents have covers, sometimes I need to reformat a mobi to a mobi in calibre before sending to Amazon but the net result is I have a cover for every one.

[quiris]

You can use my python script to side load missing covers into your Paperwhite, Paperwhite2, Kindle Touch: https://github.com/quiris11/ExtractCoverThumbs/releases

usage: ExtractCoverThumbs [-h] [-v] [-o] kindle_directory

positional arguments:
  kindle_directory  directory where is a Kindle Paperwhite mounted

optional arguments:
  -h, --help        show this help message and exit
  -v, --verbose     print more informations
  -o, --overwrite   overwrite thumbnails

[quiris]

I have also compiled standalone .exe (for Windows) and .app (for Mac OS X). The .exe and .app require no other dependencies.

usage: ExtractCoverThumbs [-h] [-v] [-o] kindle_directory

positional arguments:
  kindle_directory  directory where is a Kindle Paperwhite mounted

optional arguments:
  -h, --help        show this help message and exit
  -v, --verbose     print more informations
  -o, --overwrite   overwrite thumbnails

Release: https://github.com/quiris11/ExtractCoverThumbs/releases

How to use it on Windows:
1. Unpack downloaded zip file to your custom directory (for example: 'C:\ect')
2. Connect your Kindle to computer using USB cable.
3. Check which letter was assigned to your Kindle (for example E
4. Open command line window (keyboard shortcut: Windows + R and write 'cmd' and press 'Enter')
5. In command line window write:

c:\ect\ExtractCoverThumbs.exe E:

6. Extracting process should start.
7. Wait a minute or two for finish.
8. Safe disconnect your Kindle and enjoy your Cover Thumbnails.

How to use it on Mac OS X:
1. Unpack downloaded zip file to your custom directory (for example: '~/Downloads')
2. Connect your Kindle to computer using USB cable.
3. Open Terminal app.
4. In Terminal window write:

~/Downloads/ExtractCoverThumbs /Volume/Kindle

5. Extracting process should start.
6. Wait a minute or two for finish.
7. Safe disconnect your Kindle and enjoy your Cover Thumbnails.