title_body: Kobo Libra images appear very small
upvoted_answer: I found a hacky solution to the problem by editing the eBook's styling using Calibre.
  Importing the ebook and then right click on Edit book which opens the actual contents of the book. Now the actual formatting is done via a stylesheet (in my case called stylesheet.css).
  In this stylesheet there are the generated properties for the image sizes, e.g.
  .calibre95 {
      height: 229px;
      width: 226px
  }
  
  Now the images can be adjusted by editing the height and width of every relevant entry. I've done this via a small Python script since Calibre generated a new entry for each image and there were a lot.
  I know this is not a general solution but might help some to fix there books as well