I know it looks like it does not recognise the image format, but using this command fixes the issue, in fact i added this command to my /etc/rc.local so i can keep apparmor up and running, after that it generates all the thumbnails correctly for the differents formats of ebooks, and it doesn't display this error message anymore.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1834386 Title: Ebooks thumbnails fail in Nemo over SMB To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/evince/+bug/1834386/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
