Missing image rendering in EPUB format

[jvican]

Hi there! I'm trying to teach my sister Scala with this book and I've realized that the epub book version doesn't render images. I attach a screenshot of page 67, at the beginning of the section of "Computing with Pictures", to illustrate what I mean:

I'm using macOS Catalina 10.15, I'm on the latest version. My sister has tried on her iPad and it doesn't work there either, so this might be a general platform on the iOS and OSX platforms. For now, I've referred my sister to the PDF version, so this is not a blocker but my sister had a preference for the EPUB format.