The cover pages of some e-books do not appear on other devices due to incompatibility. The solution for this is caliber. It provides the opportunity to edit not only the cover page but also the content.

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To edit the cover page; It will be enough to edit the following line with the “Edit Metadata” option or add it if it does not exist.

<item id="cover_image" href="cover.jpg" media-type="image/jpeg">