I'm not sure it's a bug as such, but it's always been like that. I've used images elsewhere online or else I have used a label with an image in (if I want the site summary in the centre) or a regular HTML block with image (if I want the site summary on the side)
Mary Cooch (personal account)
Posts made by Mary Cooch (personal account)
Moodle in English -> Installing and upgrading help -> Softaculous upgrades -> Re: Softaculous upgrades
Jason Lane - re conversations about Softaculous on the French forums - actually there are many, by one Daniel Méthot who's a big advocate. One example here ,but I think it still is probably better if you can upgrade manually.
Moodle in English -> General developer forum -> why site administration is not working? -> Re: why site administration is not working?
Please try the suggestions in #14 My Administration block links don't expand! here Blocks FAQ
Moodle in English -> General help -> New Account authentication failure -> Re: New Account authentication failure
Look in Site administration>Plugins>Message outputs>Email
Moodle in English -> Installing and upgrading help -> Users cannot log in to a new unstallation -> Re: Users cannot log in to a new unstallation
If you go to the page Site administration>Plugins>Authentication>Manage authentication that is where you would click to enable email based self registration. Then you scroll down on that same page and you will see Common settings - make sure it says "enable"