Kindle Paperwhite Home Screen books Covers are too small

Hi,

As you see in the attached image, All books which I converted from ePub to Azw3 by Calibre shows up smaller than Amazon Store original books and with the bottom word "Personal". If I convert these books from ePub to Mobi then it will show up just like Amazon books cover size.

Any idea how can I make them all the same size "big"?

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