While I was searching for sources of book covers I have stumbled upon the following:
https://www.ereader-palace.com/get-h...kindle-ebooks/
The post describes a way to download high-resolution cover images from Amazon, higher than what you would be able to typically see on the website, using some "secret" Amazon URLs. Note that this only works for Kindle books.
Since I found it very useful and I was using it quite frequently I have decided to develop a Calibre plug-in that does the same thing. In case the book identifiers contain an ASIN at the usual places ("amazon", "asin", "mobi-asin") and that ASIN is for a Kindle book (starts with "B") then this plug-in will download the high-res cover images from the Amazon servers.
Note that until it reaches version 1.0.0, consider this an alpha version and anything can/will change. In case this plug-in proves to be useful for others, and when I'm comfortable with the quality/maturity, I'll publish version 1.0.0.
Version 0.5.1 is now available for testing: uses a new URL for downloading covers.
Version History:
Source is published here:
https://github.com/lbschenkel/calibr...n-hires-covers