Thanks for your suggestion. Here's the code of my jacket.xhtml. The book and it's metadata are in Hebrew, which is written from right to left, that's why I am using dir="RTL".
The parts of the code which I changed are in the first table, where I removed the word "Tags" and centered the remaining text. And of course, below the book comments section, I added a table with the author's name and information about the author.
When this book is opened in Calibre/Sigil or any e-reading app, it shows just fine. But as I wrote earlier, on Kindle the picture becomes tiny and the tables show an expand button for some reason.