I have encountered a problem of images not showing (X appears instead of an image) in ePub after resaving the file in Sigil or Calibre. If you view the unedited ePub that was exported from the latest version of InDesign, then all images are there.
Only several ePub readers appear not to show images (AlReader, Bazaar); most commonly used like ADE, iBooks show images after edits in Sigil.
It wouldn’t bother me if all ePubs (mine and from other publishers) behaved the same way on those viewers, but I found out that only my ePubs behave this way.
If I take an ePub produced by another publisher, images are shown fine, and when I resave their ePub - images are gone!
I think that all ePubs need further editing in editors after exporting and Sigil and Calibre are most widely used - so I don't understand how other publishers manage to edit ePub and retain all images?!
All ideas are appreciated!