title_body: Kobo Libra images appear very small I have a new Kobo Libra and bought 2 online epub books.
  I transferred them onto Kobo by using Calibre. When opening the eBook the layout is fine except that all images appear very small!? I've opened the the eBook in Calibre and there everything looks fine, the images are scaled to a readable/viewable size.
  Is this an issue with Kobo, the .epub format or something else?
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